That said the restraints might be more in terms of what having a governor like you actually means rather than making the ability not let you easily befriend one.
Governor's have a lot on their proverbial plate (and often their real one

) and can't just give away stuff to a friend, especially not one who they don't owe any favours to. A foot in the door with important organisations, maybe some higher level contacts in the local military and law enforcement, perhaps a shinier handgun if the governor rules an affluent planet.
Remember that governor's are usually part of a large extended noble family, with in-house and inter-house rivals vying for the governor position, the Administratum pressing them for tithes being maintained or increased, Mechanicus contracts to negotiate and inter-planet trade deals to negotiate in general, planetary cultural matters to attend to, a large coterie of advisors and previous friends and obligations, and a whole host of other things that limit how much aid they can really give this firebrand preacher they've taken a shine to.
It's also possible the governor is just incompetent and basically a figurehead, that happens to sometimes.