People may invade your personal space for many reasons: because they are taller than average, because they may be commuting for a long time and need to move their legs a bit, because they simply forgot or think about something else, because they come from different cultures with a different culture of what is personal space (try using public transportation in Beijing and then in Tokyo), or because they are assholes.

I think that we can just try to be humans and ask, it's not really a big deal. As I said even eye contact is enough most often, is it so difficult.

There's no need to start a war, leave along a pointless, sexist war like the proponents of the term "manspreading" are doing.