Rewriting when you are assigned to a new script is one thing. Rewriting when you are assigned to a million-line application is another, especially if that application (like most applications) doesn't have a comprehensive test suite.
In addition, any change, no matter how small, has a certain risk associated with it. Larger changes have larger risks. A risk has a very clear dollar figure associated with it. It may be appropriate to leave an application in a crufty state, because of the dollar figures associated with changing it and not changing it. I work on an application that has that exact situation. It's crufty, horrible, and needs a complete rewrite. Except, that rewrite is being done by another group and I just need to keep it limping along for another year. It's one of my many tasks; I might spend 20 hours a month on it. Yes, I could rewrite it in that time, but that is wasted effort becaue the benefits to rewriting it are only gained by amortization - you spend $100 now to save $50/year over 5 years. You are still in the hole for two years and if you expect to turn the application off in a year, is it still worth it to rewrite?
Being right, does not endow the right to be rude; politeness costs nothing.
Being unknowing, is not the same as being stupid.
Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence.
Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.