I think the problem here is that you're viewing things in isolation.
The CJ Billboard didn't affect me in any meaningful way, but that's a product of my current state of mind and the success of my transition.
However, I know how upset it would have made me back when I was dealing with people being horrible on a daily basis. When I couldn't walk down the street to the supermarket without being stared at, whispered about and laughed at or openly mocked.
The thing about coping with that kind of behaviour from other people is that it gets to you. You can feel bulletproof in the morning when you get up and you can face down the nasty comments and people spitting at you all day, but by the end of the day you are tired because you've been dealing with this at work, from your family and from complete strangers.
So when you want to buy your loaf of bread and milk from the supermarket and grown adults are cracking jokes about you, they just aren't funny anymore.
Everyone had that saturation point where they can no longer see the lighter side of things. When you're too beaten down to stop letting those words have power over you and all you want to do is curl up in a tight ball and cry your heart out.
I spent a grim 10 hours in the hospital with a trans friend who tried to kill herself with an overdose because she'd just had enough of being laughed at and harassed in public. Of the jokes and the passive acceptance that it's OK to openly make fun of trans people and say things you wouldn't say to other people.
Because you're dealing with vulnerable people who are pretty beaten down all the time, things like this billboard have the potential to be damaging - especially the discussions around them where people say all kinds of nasty shit about trans people.
I'm sure it's easy to rise above when things are going OK in your life. It's easy for me because hell, I have a pretty charmed existence as a trans person. But I know people like /u/-halcyon and my friend from hospital who don't have it so good and are dealing with a lot of bad things in their lives.

So I don't agree with your point of view. When a minority already has a suicide rate of over forty percent I really do think we should be treading incredibly carefully around them so we don't do more harm.