These were originally opened as feature suggestions and I voted for them. At some point they were moved to Live TV & DVR and the ability to manually remove the votes associated with them is no longer present:
https://forums.plex.tv/t/dvr-should-mark-commercials-then-automatically-skip-them/276472/46
https://forums.plex.tv/t/feature-req-mark-episodes-bad-to-be-re-recorded-when-possible/519772/6
The last two are already closed. And since the first is no longer a feature suggestion, no one else can vote for it anyway.
Here they are in context on my Activity → Votes page in my profile (2nd, 4th, and 5th entries):
