Interlocutor (noun): a person who takes part in a dialogue or conversation.

Use too little politeness and your interlocutor will be too busy trying to take you down to listen to your points.

Use too much politeness and your points will get buried below a ton of useless gestures. Your interlocutor will then spend more time trying to know what you want to say.

Speak politely enough to not be rude. Speak directly enough to deliver information swiftly.

Find teammates you’re close with so that you can have more direct communication. The tighter the bond, the more acceptable it is to have less manner.

Help out those who are easily offended and those who are too afraid of giving offense. Or just screen/kick them out. Some projects are too crucial to be handled by people who can’t communicate quickly.