Either she is doing Fred a favour or she really likes Mary. Can't imagine the second one because I've never seen them talking honestly. But if it is the second reason, Mary must be nicer in private as she seems to us.
And the thing with Sofia, as long as they invite her as private person, it's okay. I mean, I wouldn't invite her, but Victoria seems to be an open person who doesn't have a problem with Sofia.
I think because Vicky had to wait 8 years to marry Daniel, she is more sympathetic to CP marrying someone he chooses rather than someone who is appropriate.
I think the reason Haakon got approval to marry MM so quickly is because his parents had to wait many years to marry and were even forced to break up at one point - all because Sonia, a commoner, was deemed inappropriate. I think Harald and Sonia didn't want Haakon to go through the same experience. Turns out by current standards, Sonia was way more suitable for the royal role than MM.