I'll give you this. Parties change. So today, currently, you are correct. Anyone who doesn't go along with Trump is a RINO.Rinos lean leftward and hate trump. With an emphasis on hate Trump
Now if Reagan were president, or GWB, the definition of what a RINO is would change.
Today if you want to be a Republican you have to go along with letting your leader break any law he wants. But the opposition is held to a higher standard. You have to go along with rigging an election and you have to be anti science. You have to believe corporations should pay no taxes, embryo are humans with rights and social security is unconstitutional.