Notepad has had View->Word Wrap for a long time if you want soft word wrap instead of having to use a hard one.
I didn't know you could add two spaces to get a single newline to work though. Is that part of html or the formatting for this site?
The place the question is coming from is that I've implemented forum commenting from scratch before and it was trivial to get newlines behaving the same way in the edit box and when they are displayed and I've never seen the benefit of leaving it the way it is other than the case where a user uses hard newlines for word wrap instead of the soft wrap built into pretty much every browser's edit box.
Yeah, in fact it's actually easier, but it's also just not desired behaviour.
If you want a wysiwyg editor, feel free to implement it as an alternative setting, or it may even already exist, but forums populated by nerds have markdown for a very long time because it works well, is faster and more convenient once you know what you're doing with it and above all else the nerds (frankly rightly) they get mad when you take it away, see how much hate Confluence gets for example.
I'm still mostly just confused as to what the use case is for that newline thing specifically. I get the idea behind a plaintext editor that can handle more complex text formatting (and get frustrated a lot with editors that try to guess what formatting I want as a type), but I don't get why anyone would champion "I want to be able to hit enter as I'm inputting text without that showing up in the final output". Is that just the way it behaves because that's how it behaved in the past and people are used to it or is there a use case (or set of use cases) where this behaviour is desirable?