I'm afraid we cannot throw away all considerations for proper form
This site isn't your personal creative blog for experiments in text structure and poetry. You're not writing poems, you're writing proper answers. SE has always thrived on the community editing posts into shape to create a coherent and readable source of information. To quote the help center:
Editing is important for keeping questions and answers clear, relevant, and up-to-date. If you are not comfortable with the idea of your contributions being collaboratively edited by other trusted users, this may not be the site for you.
Yes, sometimes a specific style can contribute to an answer's impression if used judiciously. But we're not a place for you to dump a stream of consciousness or a weird poem if that doesn't add anything to the answer itself. On SE authorial control is often enough inferior to other goals, like proper formatting or having valuable content exist.
In the same way we also fix new users' posts when they lack any and all punctuation or linebreaks, when they miss to put quotes into quote markup, when they use code formatting for emphasis,... It's not expected that anyone automatically knows all the intricacies of SE markdown formatting. That's why we have community editing. The top-most priority here is that your answers stay readable and properly formatted, after that comes some degree of personal style.
But there's indeed various degrees to that and various degrees of freedom your expression has on SE.
Ampersands are an absolute no-go in proper flowtext
We have never and will never propagate l33tsp34k, emojis or any other symbology in place of actual written text, in the same way as we don't really write sentence fragments in place of proper flowtext unless extraordinary circumstances ask for a more unconventional style. You'll also notice that the logo you cite is, well, a logo, not a proper sentence in a bigger chunk of flowtext. So taking that as example is a bit of a red herring and only ironic in the sense that it quite emphasises this difference between logos/titles/fragments and proper flowtext.
Frankly, I find it, maybe not "infuritating", but at least baffling how typing three letters is more difficult than typing a special symbol and how after years and hundreds of posts of experience and practical learning ground I still have to fix these ampersands in some users' posts each and every time.
However, I acknowledge that it's not always too easy to get rid of such habits, especially in times of internet communication. It also hasn't always proven fruitful to try and reason with those users, sometimes inciting rather spiteful and annoyed reactions. So in order to keep the site going as smoothly as possible and avoid having things escalate over silly things like punctuation, I just have to bite the bullet and fix the posts again and again and again, making peace with the fact that some users just won't change. The alternative of leaving the posts in a sub-par shape is of course entirely out of the question. Fixing spelling mistakes is a primary purpose of edits.
But that's the good thing about SE's collaborative editing. You don't have to necessarily adapt your way of writing, even if inappropriate for SE. People will usually chime in with helpful edits to fix it anyway. It's not a reprimand or a humiliation to have someone edit your post, neither does it require an apology from the editor for touching it nor is it asking for you to change your ways. Other users edit your posts into shape so that you don't have to worry about it. Not wanting to double check everything you post is a reason to embrace collaborative editing since you have an entire community to do this for you, absolutely for free.
Yes, it might feel sometimes exhausting to have to fix something for the umpteenth time. But whatever, we brush it off and carry on and if neither you nor I nor that guy over there are in the mood to fix something today, maybe someone else will tomorrow. If we didn't think it's worth doing for making the site look better, we wouldn't do these edits.
Mixing linebreaks with paragraph breaks is confusing, but there's some leeway
Having proper pragraph breaks and then having the paragraph suddenly employ individual linebreaks can be quite off-putting and distracting. It's best to decide for one or the other (and SE has practically made the decision for pragraph breaks already) rather than mixing them wildly without any apparent purpose. If the purpose of some random style decision isn't apparent, the assumption is that the author is just throwing stuff out as it comes and having the rest of the community worry about formatting, which then will helpfully jump in to fix it.
However, this is less of a clear matter than ampersands, so I won't go out of my way to edit them out. Usually I fix linebreaks once, especially when there's other stuff to fix, and when the original author changes them back, it's a sign that he is committed and conscious enough about this styling to assume at least he knows what he's doing there. You could say it's just an additional barrier to make such unfortunate formatting, if not impossible, then at least a little harder to do.
What is quite a bit more off is the way you drive this in this meta question (but it's acknowledged that this is for the purpose of satire here and I haven't yet seen any of your genuine answers in such an utter mess). Breaking lines mid-sentence is not proper formatting and will be fixed unless there's an extraordinary reason directly related to the essence of the post's content.
