So if I see a woman drinking coffee at a cafe it's oppressive to talk to my friend about how beautiful I think she is? Yeah I don't agree with this at all.

If you're within earshot you're doing it on purpose so that she'll hear you. This is, of course, assuming you read what I said and saw that I specified "within earshot".

as far as approaching a woman in public on the bus, whatever.

Glad to see micro-aggressions don't real for you. Again, this has to do with a permissive culture that makes it so that men feel entitled to walk up to a woman at ANY point and hit on them. And your best-case hypothetical scenarios are a fantasy. But as a dudebro, the most you're thinking is probably that if she rejects you it's no big deal. Want to know what she's thinking? She's probably wondering what you'll do if she turns you down. Will you call her a "bitch"? Will you hit her? Will you tell that mate you keep referring to, what a frigid "dyke" she is? Or will you just leave her alone? Maybe you'll stalk her, and rape her?

Women think about these things because these things happen to women more frequently than you think. Hang around /r/creepyPMs and read the interactions women have with guys who hit on them, guys who text them, who call them, who when rejected do some of the most vile things imaginable to them.

Look, maybe you're a well-meaning bloke who is genuinely a bit blind on this issue, but the reason that women have written about this issue is because it matters to them. This isn't about you and what you want, it's about them. Respect that. Match your interests as opposed to hitting on women when they're on the street, going to work, reading at the library, etc.

I'm not your dating coach. It isn't that it's "sexist" to approach women in public, it's that you come off as a creep and you come out as potentially hostile and a sexual harasser. Have a read here if you want to express your sexual interest and sexuality in the healthy way you claim to want.

I don't see how it could be construed as sexist if my intentions were not to reinforce my position of authority over said woman

Your intentions don't matter, your actions do. You can be nicest bugger in the world. If you're walking on a the street in the middle of the night and in front of you there's a woman walking a few steps ahead, cross the street. Give her the security of having the space for herself, for instance. You know you wouldn't do anything to her. She doesn't. Just an example.