I agree that ideas should be judged on their merits but you're still dealing with human beings. Someone could approach a bad codebase and say, "Here are some w

I agree that ideas should be judged on their merits but you're still dealing with human beings. Someone could approach a bad codebase and say, "Here are some ways we could improve X, Y, and Z," but you could have another person say, "This was done in the stupidest way possible, we have to throw all this crap out." If someone approaches things politely and professionally then no one should have a problem with constructive suggestions for improvement. But people sometimes approach things in a combative or disrespectful manner and that's when you run into problems.