Good for you, keep doing what you're doing and don't listen to these people, people like them just like to stir shit up.
Relatedly, have you asked and observed your grandma using it? Might be interesting, I'd definitely read a blog post about her usability of the product as a sort of UX test.
I was the original commenter, and I can assure you my goal wasn't to stir shit up.
I simply don't like that "Grandmother" is the go-to example of someone who will fumble to understand a new concept. I know there's no active malice when people use the expression (who doesn't love their grandma, after all?), but it's a stereotype that makes older women essentially the butt of a joke.
So would you have been ok if the OP said "it's so easy to use even a toddler can use it ?"
Sure sexism is valiant cause to fight but at some point it's becoming a complete joke and no one takes you seriously anymore ! Grandma's example do apply here.
If you take a 100 random grandmas, 100 random middle aged people and a 100 toddlers and give them a basic cognitive test (not IQ) just basic stuff like
processing speed, problem-solving and tech skills.
You'd be GUARANTEE to see difference between the groups and to pretend difference doesn't exist is just plain stupid and ignorant of the real world.
If grandmas over the world suddenly want to apply to be airline pilots, would you support it ? Would you feel safe ? Would prefer your child fly with a toddler, middle-aged or grandma pilot ?
Relatedly, have you asked and observed your grandma using it? Might be interesting, I'd definitely read a blog post about her usability of the product as a sort of UX test.