I know, it's pathetic. It's partly because they don't want to pay for the staff to do the enforcement and partly probably some other reasons.
In classic British style they just try to influence and nudge people with campaigns and posters. That way the organisation doesn't have to deal with awkward accusations of racism etc
It's about acknowledging it's a shared resource and respecting the space. No loud noises, no littering, no being drunk etc
These days people act like they're the only ones travelling