Baby, bathwater.
It's never been an offence to be somewhere just for a walk up here. Trespass isn't a law. It's not enshrined in some national psyche.
Our King, or Queen, is ruler of the People, not of the Land.
Even in the Lord's Prayer...it's, "Forgive us our debts", not, "Forgive us our trespasses".
People might own land, and the curtiledge of a demense is considered private and not to be lightly intruded upon. Same for growing crops, or disturbing farm animals, but that doesn't preclude other folks having a walk, a quiet camp, picnic, whatever, everywhere else.
The issue isn't the sheer number of people visiting, it's the very small percentage of selfish and thoughtless ones. Most folks do clear up behind them, that's why we still find it shocking to come across beauty spots spoiled by litter. The roadways and towns are regularly cleaned, no one makes comment on that littering very much. We do on countryside stuff though.