"There are no mares as taxi 'drivers'"
How often do you see taxis in Equestria anyway?
"No mares as guards."
Ya got me there.
"Heck, they didn't show any mares who did something physically exhausting. As if they aren't capable to do that, or something."
- Applejack bucks apples for a living, Rainbow Dash is constantly flying around clearing the sky of clouds and practicing her routines. Fleetfoot and Spitfire are members of The Wonderbolts. Everything Pinkie Pie does is physically exhausting. Oh, let's not forget Vinyl Scratch… she's a DJ. And Derpy delivers mail.
AND everypony (which includes mares) does their part in the Winter Wrap-Up.
4) Female characters shown weak and almost useless (for example, crying scenes. In the majority of cases mares were the ones who cried.)
- Celestia and Luna are far from weak and the Mane Six are the most proactive characters in the show.
I'm sure there are stallions in Equestria that have cried at one point or another (case in point, Big Mac when his parents died) but since the show focuses primarily on the adventures of the Mane Six (and nopony can be happy all the time), that's why you see mostly mares being upset.