Is the GM ALWAYS spending Edge to resist summoning? Are they running an official Missions game?
Well, he definitely does it when players summon Force 6 spirits. I think he cuts players a break if they only summon Force 3 or less. I've only summoned one spirit at his table recently, because after a few games playing a mystic adept shaman who liked summoning Spirits of Man, I switched to playing a decker. I just started a magical character for the first time in years last month, for Neo-Tokyo. And yes, it is official Missions. I don't see a rule against the GM using the spirit's Edge to resist, so it's technically legal - just harsh. To be clear, I haven't been playing a mage for a while, so he may have discontinued this practice, but it was definitely a thing a few years ago, and the reason I stopped playing a mage at his table.
Anyway, this is already a bit more public than I'd prefer. For more details, I can take it to private messages.