As @anon61221983 pointed out, a lot of this isn’t even related to partners - potential or otherwise. The increasing emphasis on youthfulness over maturity is a problem for people in all kinds of careers. We see more media coverage of celebrities, but the pressure to look younger in order to find employment (or keep an existing job) seems to only come up in articles about discrimination.
There’s an old corporate downsizing “joke” about replacing every forty with two twenties. Looks like that’s the age when federal protection begins, too. Coincidence? 
On top of all this, for members of marginalized groups, the “standard” of attractiveness might be one they can never meet (or choose not to adopt). That could lead to unequal treatment in educational, legal, and healthcare systems, just to name a few. Efforts to make that type of discrimination illegal haven’t been entirely successful:
