Why do some users have zero upvotes on their new posts/comments?

Whenever I post or comment (collectively, "post"), it has my upvote automatically without me doing anything, so the post always starts at +1/-0.

Now I've seen fresh posts with +0/-0, so not even the user itself is upvoting.

I don't really care that much about votes, but I'm curious. Is this the user removing their own upvote, a client feature, some server feature, or some other reason?

Thank you in advance.

Edit: typos