Ash had the same level of anger/annoyance towards Trip that he did towards the guy that abused or abandoned his Pokemon.I don't see it. If anything, BW was really not serious about any of its rivalries.
Sounds like taking things serious to me.
Did Ash intentionally break the rules of the trials though? I mean even if you believe that his idiocy in the Nimbasa Gym was in character, the other problem is that bring a single Pokemon to 3 VS 3 match is kind of against the rules.Because its gym leader accepted it, and her words is apparently final? Same as how all SM trials had rules based on Island Kings' whims.
And I don't think this can be stressed enough, but normally I try to avoid believing that a writer's slip up is by intent. SM, and even other seasons have their own writing issues, but BW honestly feels like it's a deliberate middle finger/f you to viewers expecting any dignity from Ash.
Even the worst of SM arguably doesn't have that vibe.