Just? Sure it is an education issue. But it is really big UX and UI issue too. Such tricks than breaked html-tag are
- not logical (unless one is coder or similar)
- must remember one (useless) detail more
- different than anywhere else
And then is wondered why there is difficulties to get people in Discourse-based forums and why markdown is not that widely loved than here quite often so many thinks 
In Discourse is already too high demand to know HTML to write an ordinary forum post, and if Ordinary Joe/Jane must learn how to break html-tags it is just too much (I donât know if that trick has anything to do with html-tags but if it looks/smells/tastes like tag in bad UX it will be a zebra )
There is no easy AND good solutions, I reckon. The closest to good would be a black list. There is still big chance that someone will use something like mywebsite.com and get a functional link â but it is matter of high Ts and staff. And there we can educate â but it canât be counted as final or even good solution.
An ordinary user has learned that URLs doesnât work all the time â Facebook teached it Thatâs why so many knows the most common trick: mywebsite .com.