phpDip over at facebook is an (I believe older) version of this site's code base. We have the advantage of being more up to date and having more and better players, so welcome!
As for colors, I think a lot of people like them. The first two comments by phil and abge give a couple reasons why.
As for multiple accounts, that's good to hear. Just so you know, it's against the rules to have more than one.
I think a lot of people got a bit annoyed at you because you showed up on the site and immediately started making suggestions in a somewhat demanding tone. If you'd like to help out, the code base is open source, and I believe you can get in contact with the admins about what the process would be for implementing your own changes and having them incorporated here. You might also like vdiplomacy.net, which also runs on the same code, but is focused on testing new variants and features. As GOD said, there's an option there to turn the colored text off. You're also free to make suggestions, of course, but keep in mind that they require work by other people and often aren't as trivial as they might seem. Two threads in one day about different suggestions might be a bit excessive too.
Anyway, welcome! I hope you enjoy it here.