The very moment before the ToP begins, Gohan says "First, let's stick together and cooperate to take them down...teamwork...teamwork...". The very next moment, Goku, Vegeta, Freeza, No. 17, and No. 18 take off. Magetta shows up and splits the remaining earthlings apart. That's when Kuririn and Tenshinhan get eliminated. The fact that teamwork is important, but something Universe 7 will struggle with because of the type of guys they are, is established right from the beginning.
Before the tournament even begins, Beerus tells them they need to work together. Universe 11 is the only team with all 10 members for a significant portion of the tournament specifically because of teamwork (Whis says it as they're taking down Berserk Kale). It is revealed that when Whis trained Goku and Vegeta together, he was tricking them into working on their teamwork. Etc. etc. etc. Perhaps you're only going off of the anime? Even so, the fact that there are 10 members per team fighting at once instead of just one-on-one battles should tell you something.
That's an...interesting point of view. I'm not really even sure what you mean. They work with Freeza because there is a larger evil at play. It may acknowledge that Freeza is strong/smart/useful, but it doesn't in any way validate his ideals.