In regard to Tim Shaw and perhaps other characters, the reason they didn't "just" tell off Trask was that circumstances didn't allow it. Trask had a hold over Shaw, and as long as he wanted to marry Charity he couldn't "just" tell Trask to shove it. It wasn't because he was a "wimp".
A lot of people like to say "I don't take crap from anybody", but a great deal of what life is about is taking a certain amount of crap from people. Those who can't can create a lot of problems for themselves.
I like Shaw, and his sarcasm and commentary on Trask, and his trudging onward despite that twisted idiot Trask cracking his whip all the time.