University education is weird. Research profs (who make up a large fraction of all profs in a typical R1 institution), are hired for research ability and are only minimally evaluated on teaching ability. Furthermore, few research profs actually receive any kind of mandatory training on how to teach; a typical research prof might be assigned a course to teach and then just let loose to do so on the first day of the semester. If a prof actually cares they may attend some optional teaching training - but I stress that these are optional at many of the institutions I know of. (I suppose if someone gets really bad teaching evals they may be advised to attend said trainings - but for a tenured prof, that's just advice).

Worse, a decent chunk of research profs will treat teaching as a burden that just has to be done - a distraction from their exciting world-changing research. So, you get attitudes like the ones you mentioned.

I'm actually not sure why the system is set up to assume that profs who are good at research are automatically suited to teach classes, but that is how it's setup.