Personally, I don't think anybody in California thinks Snoop created the term, and a lotta people involved with rap do know that The Bay came up with a lotta that.
However, I do think slang is somethin that doesn't need to be tripped on to that extent. Everybody in the nation (and maybe world) borrows each others slang, and it can end up leading to a slippery slope. L.A. people hate seein NY gangbang and call em copycats, but then somebody from NY will be like "well if we are copycats for havin crips n bloods, then y'all are copycats for rappin because we created rap" and shit like that always goes back and forth.
I feel y'all that you hate when people steal slang and act like they don't know where it came from, so hopefully it can be known nationwide. But with Snoop, he has always been cool with 40, and I think people see him as gettin credit for it only because he is Snoop and is one of the biggest, top 3 rap artists as far as cultural influence goes.