There might be a universe in which magic exists. However, there is no universe in which I exist and magic exists. That’s because I was born into a mundane version of the universe, so there are infinite possibilities, but because my existence in a magical universe is 0
That doesn’t really follow. Specifically, you’re putting way too much credit (infinity times as much credit as you should, in fact) on your ability to know exactly how your universe works. You’re saying there are zero hypothetical worlds in which you are the person you are now and also magic exists. I’m sure you can see how this is not true; for all you know magic is very obvious in your world and you just got mind-controlled, a minute ago, to your current state of mind. Or maybe you just never noticed it and hence grew up thinking you are in a mundane universe, which is very unlikely but not probability-0. Or one of many many other explanations, which are all unlikely (nothing involving a universe with magic in it is going to be likely), but very much not probability-0.
Not a good example. “Defending X” is a much stronger requirement than just “pointing out that a specific argument against X is invalid”; the latter is done by everyone who likes seeing good arguments rather than bad arguments, and isn’t a sign of liking X.
(The most pro-russian (as in, supporting the russian-ukraine war) stuff I’ve seen was various memes from lemmy.ml and lemmygrad that ended up in popular. I’m having trouble finding a better example than that; in particular, because Lemmy’s search is bad and doesn’t seem to allow for searching recent comments from a specific instance, and also refuses to give me more than a few pages of results.)