One of several tensions between trainees and PI should rightfully be over the "way things should be" and "the way things really work" in science.
The mentor, usually, plays the role of the cynic when it comes to getting papers accepted and grants funded. The trainee, usually, plays this role when it comes to collecting data.
Papers are an interesting situation. Excessive amounts of "this is the voice of experience talking" can lead to a defensive crouch. Conservatism. Never drawing bold conclusions or asserting strong implications.
OTOH, experience is good for something. Knowing what triggers reviewer ire can be the difference between the paper getting accepted instead of being rejected. Naturally, you as PI know it will get in somewhere eventually but trainees have timeline issues that even they might not fully realize.
How inclined are you, Dear PI Reader, to let the trainee submit the paper the way they like it when your bet is that a particular thing will make the reviewers crawl all over you?
Do you let them learn the lesson the hard way?