I sympathize with this feeling - I think that the frustration that is created within members who actually care for this forum content and well being is far greater than the "consequences" of those same abusers. I'm not diminishing the work from the mods who delete these threads, but I'm sure that it's also tiresome for them to be always deleting the same kind of threads/posts created by the same user(s), especially when the rules being broken are constantly the same.
I fully support free speech - I'm from the opinion that one of the most powerful and beautiful things of live is free speech. People can say whatever they think about a certain subject and it's up to the listeners to make a critical judgement and determine if they're are either against or aligned with that vision. That works well for Facebook/Twitter because they are (supposedly) un-moderated platforms and if I don't like the person I can simply block him / move on with my life. The problem in communities such as our is that that we can't keep "forgiving" the same user over and over again by continuing to break the forum rules (and most of the time the same rules) - if he/she doesn't respect the forum rules, why do we have them in the first place? Just for them to be guidelines of correct behavior?

I totally understand that newer members may occasionally break the rules and a couple of warnings should show him that perhaps he should think twice before making future threads or at least re-think his way of posting. But when that fails, why should we just continue to erase his threads ? If he/she continues to show a lack of effort or the rules, why should we continue to increase the load of work for mods regarding his/her threads?