beat on
verb1
Figuratively To talk at length; to go on and on; to rant or expound.
- She's beating on about poor service.
2
Figuratively To criticize, impugn or shed a bad light on (a group or topic) for political gain.
- She's unpopular enough that photos of her are used in elections to beat on liberal candidates.
- You guys are always beating on immigration, but it won't win you this election.