LEGO is a trademarked name
Correct way to talk about Lego bricks is to say Lego bricks
"Pass me all your Lego!" Is not a correct sentence. "Pass me all your Lego bricks!"
If there were 15 Lamborghini cars in a parking lot. You'd say "That's a lot of Lamborghinis"
Lamborghini doesn't have to worry about Lamborghini becoming synonymous with "cars". So Lamborghini doesn't care.
If everyone keep saying "Legos" for "Plastic Bricks". Lego could have a trademark situation on their hands, so they try their hardest to stop people calling the individual plastic blocks Legos.
It being plural is like a myth.
I have many Lego. I enjoy playing with my Lego. My Lego makes me happy.
I love playing with my Lego plastic bricks!
I love playing with my Lego!
I love playing with my Legos!
So everyone you know in person says the second one?
"I play with my Lego often"