It seems to be a coastal "resort" thing: Newquay and Skegness have similarly over-officious staff, especially in the summer. Perhaps they get some sort of kick out of it?
Skegness is done for a number of reasons.
Firstly the trains come in looking like they've had the rear end of a dust cart spray rubbish up the inside and the only way to get them cleanish is to do it quickly in the time available without climbing all over passengers and luggage.
Secondly the trains are tanked there and owing to the platform layouts the hoses are everywhere, and that's a modern risk assessment process for you. They can't be tanked at Nottingham at present so the only way to manage a round trip is to make sure they're done properly at Skegness.
Thirdly all the dross and idiots in the world travel from there and make the station staff and traincrew's lives hell. If we can't weed out any dangerous types (it's rare to go a year without the station staff having guns, knives etc pulled on them) or fare evaders at the barrier then we are stuck with them until we can get police out from Nottingham, Peterborough or Lincoln. Boston and Sleaford stations are only manned part time and after that you're on your own for a long distance. The trains are often also so full in summer that the only way to do an effective revenue check is to do it at the barrier and it also allows Scummies who won't fold push chairs etc to be locked out until they do.
Finally having a charge can cause fights and arguments to occur whereas the barriers allow us to 'drip' the passenger flow.
Sorry if it makes enthusiasm difficult but it's really one of those locations where I'm not interested in anything other than staying safe. We've had numerous staff assaults this year, yet again, and it's done the way it is to try and keep violent issues to a minimum. These places attract a lot of scummers who are difficult to manage at the best of times and allowing a free for all does not work out well. This year's tactic has involved station staff, train guards, and managers from all over the business descending to process people as quickly as possible and safety in numbers does help.
Skegness station maintains year round staffing from opening to closing because otherwise it would not be a safe environment and the staff tend to behave accordingly.
That being said, if at a quieter time you ask to go and take some photos of the signals or whatever I can't imagine the staff refusing you. Don't expect to be accommodated at peak times though because the situation with overcrowding has reached critical levels with people being left behind from many trains and the staff are unlikely to be minded to go out of their way for hobbyists. Also don't expect to be allowed to board the train without rejoining the queue as the customers in question are not fond of queue jumpers.
It's sad that this is how it is, but that seems to be the lot for these kind of places now.
If I never had to go there again it would be too soon which is a shame as it's a hugely interesting railway line from an enthusiast perspective - but I think the amount of times I've been threatened and sexually assaulted (I am sick of ****ed up hen parties grabbing my genitals, I'd be thrown in prison if the boot was on the other foot) and colleagues have actually been physically and verbally assaulted means I'd be quite happy for it to be ripped up and closed - it's just non stop problems from April to October and again on Fridays and Sundays for the Butlins theme weekends all winter and I dread going up there.