The site's community rules state that we need to be civil to one another, and that rule applies to users at all levels, including to the site's builders, contributors, mods, and admins while processing the mod queue, and interacting here in the forums. Attacking one another has no place, and escalating disputes is never helpful.
That said, we do have certain users that intentionally antagonize those in the mod queue by posting things egregiously below the quality threshold (or outside the acceptable topics) that will ever be accepted here. When dealing with these posts manual deletions are warranted, and sometimes it's difficult not to be a little dismissive in dealing with that content or those uploaders. Some of these people will continue to create new accounts, and generally go out of their way to troll the site. Personally I don't agree that this was one of those cases, and in general I prefer that the feedback provided when flagging, rejecting, and deleting be constructive or at least non-combative. Again though, some of those trolling cases are frankly intended to be perceived as garbage. This was not one of those cases, but those cases can flavor people's reactions to things they perceive as similar. While I can't say a manual deletion was warranted here, I do agree that at this point, those works as they are were unlikely to be approved.
As for self-uploading, we do discourage it here. It's not banned, and occasionally there are self-uploaded posts that are well received. Too often though, it's too hard for a person to distance themselves from their work and gauge quality as objectively as is sometimes needed, and it's far too easy to take critique of the work as a personal slight. We almost always prefer that artists post their work elsewhere (Pixiv, Twitter, Deviantart, etc) and allow a third party to be the judge of it's suitability here. All artists need to start from somewhere and grow from there, and I can see that you are earnest in developing your skill and want to share your work. As others said though, Danbooru may not be the best place for that. Other communities are aimed more for that sort of thing, or if you joined the Discord there is a section for those who are learning and would like constructive feedback.
In short, we should all do our best to be more civil in our interactions with the site. We should also be cognizant of how the site works, and how it is intended to be worked with. Know also that not everything is approvable, that feedback to a work is not generally meant as feedback to a user, and as much as possible avoid hard feelings when opening one's own work up to such criticism (as will always happen when posting to a site like this one).