Is it easier/more acceptable for idols to openly admire western artists than other Kpop acts?

Definitely. Kpop idols are allowed a TON of leeway when it comes to Western artists.

Imagine if a Korean idol put out a song like WAP. That idol would be cancelled in a microsecond. Then imagine if BTS or BP collabed with the idol, both groups would be cancelled in a microsecond as well. Yet, they got no pushback for collabing with Megan and Cardi. Nobody in Korea blinked an eye.

Stayc put out the best group cover in recent memory of a Western song, the megabop Kiss Me More. No problem. But they wouldve been cancelled in a microsecond if this was a StayC song. Yeah, it doesnt really make sense, but there you have it.

rookies praise senior groups all the time but popular groups rarely mention other groups.

Yes, it would be a war zone if a popular group mentioned another. Even junior groups and rookies get attacked sometimes by fandoms of their senior label mates if they mention rival groups from other companies. Some groups even get called clout chacers for covering popular groups.

Kpop fandoms rivalry and politics are too toxic to allow this.

I feel like for juniors it's easier to admire senior groups and for senior groups it's ok to mention like up and coming groups

but that level of admiration is I guess "restrained"