Memes

Lego did a large behavioural study on this because this was their assumption, they thought they were doing completely gender-neutral stuff, but even controlling for parents’s biases their stuff wasn’t gender-neutral when it came to actually be interesting to kids.

Interesting. I can't seem to find anything on this study, but maybe that's just my search engine not providing very relevant results.

What is a relevant result is the study from just a few years ago that Lego also commissioned, which they're using to justify making their product lines more gender neutral, after finding that:

"girls today feel increasingly confident to engage in all types of play and creative activities, but remain held back by society’s ingrained gender stereotypes" and that "Girls [...] are more open towards different types of creative play compared to what their parents and society typically encourage."

And they found a significant effect from parents pushing their kids into certain interests and hobbies influencing the behaviors of children:

Our insights further indicate that girls are typically encouraged into activities that are more cognitive, artistic and related to performance compared to boys who are more likely to be pushed into physical and STEM-like activities (digital, science, building, tools). Parents from this study are almost five times as likely to encourage girls over boys to engage in dance (81% vs. 19%) and dress-up (83% vs. 17%) activities, and over three times as likely to do the same for cooking/baking (80% vs. 20%). Adversely, they are almost four times as likely to encourage boys over girls to engage in program games (80% vs. 20%) and sports (76% vs. 24%) and over twice as likely to do the same when it comes to coding toys (71% vs. 29%)

And they even showed that kids felt pressured not to engage in cross-gendered play, even when they wanted to:

71% of boys vs. 42% of girls say they worry about being made fun of if they play with a toy typically associated for the other gender.

Now, a quick note on your other point.

If you say “there is no difference at all between men and women” you’re bound to essentialise everyone towards your own gender.

I don't believe there is no difference at all between men and women. I simply believe that a lot of the things we say are inherent differences are actually not as inherent as people tend to believe.

For example, I've seen no evidence that women are inherently more kind/caring/empathetic than men in any biological way, only that society socializes them to be so, and thus we see that trend perpetuated over time. Yet if you ask most people, they'll assume there's something biological that makes women more like that emotionally.