You have to keep in mind that Itch doesn't apply any filters or requirements to the offers in that subforum; anyone can apply or offer. So you're going to find all sorts of people: professionals, non-professionals, good people, bad people, etc.
In my personal experience and what I've seen, I'd say that the experience is generally quite positive, and I'm sorry to hear what happened to you. Someone blocking you without any explanation is very abrupt and rude, but it's not common. I recommend you keep looking and promoting yourself.