I was taught in early rhetoric and composition classes that it is poor style to include "In my opinion" and other qualifiers in pieces that are clearly rhetoric

I was taught in early rhetoric and composition classes that it is poor style to include "In my opinion" and other qualifiers in pieces that are clearly rhetorical or opinion based. The repetition is unneeded. In engineering discussions it is very common to differentiate between opinions and knowns. When discussions happen between people who don't agree on these things, someone gets annoyed. The engineers get annoyed when people state opinions as fact and think the other person is making unjustified assumptions. The non-engineers get annoyed and think that the other person is being pedantic.