You feel compassion for the animal because you do not believe in their agency. If a dog is in a bad position they cannot change it themselves. Without a home they will simply be at the mercy of the wild or with a bad home they could be tortured.
If you thought the dog could recognize the situation and change it then you would not feel the compassion. You would instead ask why the dog wasn't doing that.
You are not desensitized. You simply believe in hyper agency. That because humans appear to have free will that we can completely control our destinies.
It's not an opinion at all but the reason this bear and the puffin are so hated. You are seeking validation for your ignorance. You feel as though you should feel for people but you don't. Rather than admit "I don't view individuals as complex people, but rather flat caricatures I create when I see them". You post this opinion to bait people into upvoting it so that you can kick that can down the road some more.
If people upvote (which is exactly why "some may relate" is on the end). Then your opinion isn't ignorant but a confession. You can go on with your life not feeling bad anymore about how you view people. Renewly validated by your successful post.
This of course lasts until the next time you question why people can suffer for so long if they can somehow magically change their situation. You may notice that kids born to shitty parents have shitty lives, they never quite get it and go on to have shitty kids etc etc. You may notice that humans are the only animals that seem to have these states of poverty. Maybe it's not a result of an individual person's actions at all but the end result of complex nation states exchanging resources for far more than just sustenance.
If you do notice these things what do you do? If people really are bound to the circumstance they are born to then that means you might be a bad person for not feeling compassion for them. Plagued by this notion that you could be something you dislike you search for a reason. It must be because you have become so calloused that only animals can warm that frigid heart. It has nothing to do with you falling victim to human bias and then choosing to avoid personal emotional turmoil.
We do not control our behavior as much as we think we do. When you make a choice in the moment. You aren't really making a choice at all. You are just processing pre understood knowledge. You do not gain a lot of insight from what's immediately in front of you. So most "choices" aren't anything more than processes inputs.
We only make real "choices" if we do at all, when we practice mindfulness. This is called many things depending on when and where you are from. Meditation, prayer, reflection, deep thought. It's essentially entering into a feedback loop of internal environments. You take the past things you have experienced and you sort through what happened and your response. Specifically looking for the ones that cause emotional response. When you find something that makes you feel, fear, guilt, shame, grief, anger, jealousy, envy etc etc. Then you know what you need to reflect on and sort out.
This is the only way anyone has every really changed their behavior. If you cannot do it then you won't, if you don't do it then you can't really change how you behave. You are constantly at the mercy of your environment. Great if you have it well off but terrible if you are born into poverty.
We do not practice mindfulness. I know about it because I have PTSD. It's part of my therapy in getting better is to consistently reflect on why I feel the way I do about things. To look deep and not lie to myself. We want to run from shitty emotions. We want them to not be true. We do things we don't quite understand and rationalize it away.
This meme was made because OP is guilty and is suppressing it. On some level they believe that they deserve compassion. As well OP also knows they are a human just like any other. The compassion felt from the OP towards themself, and other animals is obviously in contradiction humans being both like OP and as well as being an animal. This dissonance comes forth as an emotion. The response is then to make that feeling go away. Since OP is a redditor they have chosen to turn to the opinion of their peers (other redditors) to relieve the dissonance. Once OP has the upvotes they can move along with social weight to their ignorance.