"it's" is an actual mistake, but the rest is Tumblr dialect

I don't speak Tumblr dialect natively and therefore can't explain it, but I do recognize it and can confirm that the capitalizations are done with explicit intent and meaning. None of them are random or accidental.

Huh, apparently it’s my curse to try to read meaning into every nuance of writing, regardless of whether any was intended. Stupid authors for training us to do this.

I'm pretty sure it's common for people to write phonetically. I commonly write "are" instead of "our", but I fix most of my mistakes during an edit. The "it's" mistake is also common, although that's usually a problem with my phone's auto complete.