They are heavy and require strenght to be driven. Plus, as I was explained, your own weight limits how large motocycle you can comfortably drive.

No, they do not, and no, it does not. Your height is the only limiting factor. A short person on a tall bike will have a hard time. Everything else is a matter of balance, not strength. You hardly use your muscles, just the engine.

As with any tool it depends how you use them - lane splitting is indeed very risky but by no means a requirement.

When people think motorcycles, they don't usually think traffic and commuting.

Yes, but I'm not sure how it relates to the discussion

They're probably alluding to the stereotype that boys are more adventurous and girls more risk-averse, which informs why motorcycles are marketed mostly to boys/men.