So you are allowed to object to abortions and protest then in any designated free speech zone with a proper free speech license. Simple as!

Can I tell someone not to drink outside of a bar?

In certain public spaces? Yeah! Probably a hell of a lot fewer of them in the UK than many countries though, including your land of the free.

This is just an argument ad absurdum. Please be real.

Most bars have signs saying not to leave with an alcoholic drink.