The article mentions camp fires, damage and littering. Certainly under current covid rules none of that is allowed/legal but even in normal times, causing damage is an offence.
I think the authorities come down hard on the types of folks in the article as they are breaking at least one law but would turn a blind eye to an obvious outdoor lover camping discreetly alone in the hills as they are breaking no law (current covid rules excepted, but I still think the two "types" would be treated differently).