The MB is a sort of rival group. The Saudis are all about preserving the Saudi royal family and its authority (and money), and the MB is of no help whatsoever in this project and in fact is a threat to them.
This isn’t altruism and it certainly isn’t an onset of modernity, but even the Saudis realize that the society that the MB wants to install throughout the ME - including, of course, Saudi Arabia - is not going to do any good for them or their country.
uncertain here ... have noticed the saudi royal do encourage snakes such as the rebels in syria though. Not a fan of assad though and certainly not a fan of the Saudi royals.