the other side cheated."

That sure sounds familiar...

I think the accurate take is that the both the GOP and the Dems have crazy elements in their parties that are unappealing to moderate, suburban voters that often swing elections in many purple-ish states/districts. When the Dems are in power, the Rs are going to try and paint the local candidates as compatriots at worst and enablers at best of folks like AOC, Bernie, etc. The Dems are obviously going to try the same thing with Trump et al (or try to draw parallels to abortion law in Texas, etc.)

This type of attack is more effective against the party in power than the minority party.