Sometimes you need to type a long reply that consists of many paragraphs and wrapping that text within a tiny textarea box makes it hard to understand and to follow as you type. There were many times when I had to write that text within Notepad++ for example and then just paste the whole reply in that small textarea. I admit I also opened the DevTools to override the
resize: nonedeclaration but that’s not really a productive way to do things.
Removing the default resizeability of a <textarea> is generally user-hurting vanity. Even if the resized textarea “breaks” the site layout, too bad, the user is trying to do something very important on this site right now and you should not let anything get in the way of that. I know the web is a big place though, so feel free to prove me wrong in the comments.
This must have been cathartic for Catalin, who has been steadily gaining a reputation on Stack Overflow for an answer on how to prevent a textarea from resizing from almost a decade ago.