Google - is this sentence correct (no one aids a totalitarian regime except they love them)?

It is correct, but people don't usually talk that way. Using the negative subject "no one", people prefer to say "unless" instead of "except", and a regime is "it", not "them". (A regime can also be a collective noun, so "them" is ok if you want to say that.)

BTW, it is "the" regime or "a" regime but not both.