SHORT VERSION
Be patient and make your point again and again. The truth is on your side but you are dealing with pathologically brainwashed people. In light of this, find anything they care about: their career, their money, religion, their girl, their sport, their heritage, identity, family, anything, and use the "uncomfortable" truth in that they already agree with to break into their belief system.
For your atheist friend, you could say: "You either believe in evolution or you don't" Then link a good HBD Chick article. And then leave it for awhile. Do not dog them. When the time is right you can push further.
One-on-one offline discussions are different.
LONG VERSION
Studies have shown that a human can be brainwashed in about 72 hours. If deeply immersed in propaganda, the human mind is frighteningly plastic. Most Americans and Euros have undergone years, if not many decades, of heavy liberal propaganda. Most people know the truth when they have the right information, but the brainwashing will prevent them from internalizing it, accepting it as part of their identity, or the reality they face. They experience cognitive dissonance.
When dealing with a victim of liberal brainwashing you need to realize they may become emotional and volatile in the same way a former cult member or drug addict refuses to admit the truth that is right in front of them. Keeping this in mind, you need to be assertive awhile patient. You need to accept that they are taking baby steps. Any progress is a victory. It's usually two steps forward, one step back for awhile.
There is an enormous difference between online debate and real one-on-one discussion. I'll discuss the online first, although the one-on-one may be most important considering the Thanksgiving/Christmas season is coming.
As far as online discourse ... there is a virtually endless ocean of idiotic nonsensical memes from which liberals can draw upon. What I call "jabberwocky politics" is a huge asset to the left. They say incoherent things they know are untrue and they feel very smug about them. Therefore, anyone who uses a "meme" (online pic/graphic/video) should be laughed at and treated in a childish manner. Many adults use these moronic liberal memes, so it is best to just troll and walk away unless they try to prove themselves by attempting an adult discussion.
In a direct discussion with someone online who may be open minded you need to take a more tactful route. I'll use your discussion with your fbook friend as an example. The key is to make an assertion with which he can agree and leave it at that for the moment. Take SMALL STEPS, then revisit.
FBOOK FRIEND: Well all people are the same humanity, all humans are equal.
YOU: But I believe in evolution, so I just see things a bit different here. People are different all over and what you're saying sounds like creationism. Maybe you should check this video out (Hjernevask series here).
FBOOK FIEND: blah blah, changing the topic, liberalism, memes, blah blah.
YOU: Yeah, I just think it's obvious that evolution is real so it seems odd to be in denial about it. But I don't want to talk about it now. Check out that vid if you can. Have a good day man!
NOTE: If you are "working" someone who is "open minded" at all, do not push too hard. Let them take the baby step and make them more interested in restarting the conversation. Otherwise you will come off as evangelical and annoying. The human mind is naturally interested in people who retain a bit of mystery, so don't blow it.
In one-on-one discussion, such as around the family Thanksgiving table, remember your opinion is more powerful than you may imagine. The human mind is wired to tune into the thoughts of assertive young men. We are the center of ideological life in the ancestral environment and the current environment. People instinctively know this.
To make a general drive towards DE thought around a liberal table, make a statement like "I was reading ______ and it makes me so proud of our European heritage! It's so upsetting to me that people are trying to stamp that out."
With any "open minded" individual (a liberal who is capable of discourse), you want to keep it direct and simple in the beginning. Identify obvious problems and make clear common sense solutions. Do not talk about complex esoteric ideas.
The aggressive liberal can be put on the defense and held off with questions alone. If you ask the right questions (the most obvious ones) then you will "win" any discussion, as long as you chill and do not overdo it. Use their ideology against them.
FEMINIST AUNT: So sad what happened in Paris.
YOU: Do you think we should remove all these muslims before it's too late?
FEMINIST AUNT: Oh no. This has nothing to do with that. Most of those people are widows and orphans, oh so sad!
YOU: So you agree with the muslim attitude towards women?
FEMINIST AUNT: Well, no, I just think they're not all terrorists.
YOU: Yeah, but they were. We can drop it, but it just seems like the situation with muslim women is really bad, so. .
Take control of the end of the conversation if possible. Make a point or pose questions towards the liberal and then end their line of reasoning so that they appear to be hung up on something obvious.
I personally have a shitlord family so I don't have to worry about this, but I've seen other people fuck it up a million times.
So, if you are not a pro at discourse and you get into it with a liberal during the holidays, you need to make an assertive point and then withdraw. You withdraw by making your point and then saying "I'm done talking about it." Smile, then do something else.