The last time I was in San Francisco 3 years ago, most restaurants refused to seat a solo diner at a table, insisting that I eat at the bar.

Is this still a common policy?

Yes. If you have no friends you eat at the bar in SF.

Huh? That's pretty hard to believe. Of course if you didn't have reservations and they offered to seat you at the bar, that's different. The same thing often happens with two people without reservations.

Good to see that the morons continue their need to ruin every public domain on the internet. At least it keeps them off the streets where they can play with themselves in private.

Never heard from anybody that a single person would not be seated! Why don't you call ahead, make reservation? And please don't say "most", it's just not true!

x at "nospam" I assume by the idiots you are referring to yourself. The reason you aren't getting any helpful answers is because your post is so stupid. Do you really expect us to believe that you think there is some sort of local law that forbids restaurants in SF to seat single diners at tables. If this happened to you once, it is probably because there were no tables available.
Or if you want an actual answer to your question, then here it is:
NO!