Isn't it illegal for Google to try to force you to apply your Google login to access other Google products?

I have a Youtube account that dates back before Youtube was gobbled by Google. Anyway, whenever I open my Youtube account it wants me to use my gmail login to access but I always use my Youtube login. I like to keep it separate. Anyway, if I have my gmail acct open in another window it automatically stops working and I have to close it and reopen it. When I do that then my Youtube automatically boots me out of my account. It's very annoying and I'm sure its designed to be that way so one will just give into a more seamless online experience. Imao, its just about data collection and they purposefully make the online experience a hassle to get one to do what they want. Isn't this unethical? A form of corporate cyberbullying? Does anyone out there feel me?