Is it normal to talk about girls like that at the workplace? seems so weird and would definitely result in a HR call
It's not uncommon in most countries. Regardless whether they're first or third world. Straight men, when in groups by themselves, tend to act like bros unless they're purely competitive. Group fantasy about an attractive female coworker is not uncommon.
This isn't Japan specifically. This is any patriarchal culture with recent gender equality where you have women in fields traditionally seen as "men's work".