I am really confused about how token rates increase and decrease. Someone said it depends on the token traders.
You mean how the prices change? Well, it is a market so if many people want tokens and there is a limited amount, sellers will ask for a higher price. For example if everyone all the sudden wants oranges, the supermarkets will sell them more expensive.
As for a more detailed explanation, tokens are very different in nature, some of them represent projects that will change a service for the token, other provide pasive income... so the price will depend on the price of ethereum in general, but also on the perspectives of the token being valuable.