This one of weakeness of Misty always had in this season of being too in love with water Pokemon that she doesn't cares about anything else. For an example for this behavior is when Corsola tackled Psyduck and Misty not caring that Corsola attacked her Pokemon.
I donpt consider this as weakness. They were traveling through Whirl Islands archipelago filled with all kind of new water pokemon never seen before. For water trainer like Misty who has deep love and appreciaton for this specie it was completely natural and within character to be enthusiastic about them. Especially since she never saw many such as Corsola before.
Not to mention your exaggerating. Just because she was pumped up over catching Corsola does not mean Misty put this over safety of her friends and others.
With Ash and Brock well being always being her first priority and than anything else. This was proved countless times when Brock was sick, Ash wandered alone in danger with Misty not wanting to wait suggesting to look out for him etc, etc).
I wished that Corsola said it was sorry for tackling the other Corsola out of their home. It was Misty's Corsola fault that this happen in the first place.
Misty cannot be responsible for actions of wild pokemon. During time Corsola rammed into other pokemon it wasn't even her pokemon.
The rest of the episode is really boring and be called filler.
I noticed based on your reviews on pretty much any Misty focused episode how you consider them "boring and pointless". I wont get into that since its matter of personal preference of what will entertain you or deliver excitement. Or wont.
With Misty personality and interests simply not being your cup of tea.
However this episode wasn't filler. Since Misty caught new pokemon and we saw some character development for her in becoming more determined than ever before of achievng her goal of becoming water pokemon master. This can be notioced when others expressed doubts over Misty suceeding to catch strongest Corsola on that island; with Misty reply being" "if i ever want to become wazer pokemon master i know i have to catch this Corsola". In oither words her message was how she cannot give up easily and let first bump stop her.
In general whole Whirl islands served purpose of Misty sorting prioritires and what she wants to accomplish as water pokemon trainer.
This was only further conmfirmed after losng in Whirl Cup knowing she still has long way to go and reassuring her belief of not choosing wrong path to walk upon. Saying she came to realization how she loves water pokemon more than any other.