Two questions since you ask what I think.
1. Are the brook trout native?
2. Is it legal to kill the brown trout you catch? Or brook trout for that matter.
If the answer to #1 is "yes" then it is probably better for the stream and the native brook trout that the brown trout are caught and killed.
If the answer to #2 is "yes" then nobody has a gripe coming.
I don't have a dog in this fight but others should not be scorned for participating in a lawful activity
fishbum