The typical way to avoid this particular problem is only to load the content via JavaScript while copy/paste are presumed disabled.
You can just use a browser dev tool like the chrome inspector to copy the text. I don't know what the big deal is.
What's to stop you from removing the event listeners disabling copy and paste through the console/dev tools?
You could use that CSS rendered font someone made a while ago to make it into an uncopyable text.
Screenshot to an OCR reader defeats that really quickly.
This whole argument about copying is rather silly, at some point the text must be transmitted in a human readable form. At which point it can be recorded either electronically, or in the most difficult case by writing down manually what must be copied. Everything else is a question of degrees.
If you happen to be on corporate computer, access to developer tools can be disabled via group policies.