I suspect this is more to do with not wanting to handle or let others see the negative comments against wetherspoon e.g. about their Brexit stance or quality of their food. They are a notoriously difficult place to complain to and usually tell you to take up any complaints with the local manager. I found this out first hand when it was the branch manager himself who served me the worst scrambled eggs on toast I have ever seen! Head office was not interested.

Trade at wetherspoon will not be affected by moving off social media and, indeed, others will not see criticisms directed against Wetherspoon e.g. in replies to their social media messages.

Plus this is a good bit of advertising for them by coming off social media.