But the footsies are in fact really stupidly cute. She's (he's? it's?) just statin' a fact. Might as well shank 'em for calling a bright day beautiful or a flower possessed of gorgeous scent.
Yukkuris tend to, take too seriously their "cute aspects" to the point of brag in a annoying and delude way, this had escalated to the point that humans abuse them at the first hint of self promotion or self praising, some sort of answer mechanismn to their absolutely shallow and childish mindsets and exclamations.
A Sad reality, but, can't be helped, their arrogancy brought it up themselves.
Also, the way I read this was that mister somehow gave Reimu those "footshiesh" (they're yukkuri, I see no reason that any mister with a boxcutter, some dough and some orange juice couldn't modify their yukkuri) and she's thanking him for them.
But mister just wanted to fuck with Reimu and cuts them off as soon as she gets attached to them.
MRC way to miss the point "reimyu's mister footsie" is her foots, they tend to give the title "Mister" to a lot of stuff, mister fire, mister water, etc. mister footsie clearly refering to her foot, it has nothing to do with the mister giving her foots.
Besides, i don't think that's how yukkuri patching work, it's known that humans may fuck up the "Foot muscle" by remplacing the dough with flour and orange juice, because it isn't their "naturally grown" dough.