Can someone be a Muslim by following less than 100% of the tenets?
Ask evangelical Christians and they will live by the Bible which is why they seek to convert others. According to them, those who do not convert others to Christianity are violating the rules of Christianity and some of them even go to the extent of saying you are not a Christian if you don't do it.
It is the same with Communism. In general, if you are for a state controlled economy and cheer and support Communism despite being religious, consider yourself a Communist. This is the case in Latin America.