Is it not likely that the double-checking of tickets is to prevent people getting on the wrong train, which might be something that happens a lot there because a lot of passengers will be (a) occasional and (b) inebriated and/or under the influence of something else?
That may be the claimed justification, yes. But if so, why aren't the automated barriers left open during periods where manual checks take place? Again, double checking is something that simply doesn't happen anywhere else on the network, and is utterly nonsensical.
It's only analogous to showing your boarding pass to enter airport security, then again at the gate, and (with some airlines) a third time at the aircraft door. I don't see what the huge objection is.
How about the fact that Blackpool North isn't an airport?
The first check at an airport stops randomers from entering the secure part of the terminal, or potentially buying duty free despite not travelling - though they're unlikely to be saving much!
The second check is the first opportunity the airline has to check your documents etc. are in order and that you're booked on the flight whose gate you're at.
The third check is fairly rare, and generally only happens if there's a bus or walk from the gate (as you could have walked to the wrong plane), or to direct you to the correct class/part of the aircraft on long-haul/wide-body flights.
Only the second of these checks has any relevance to a railway station like Blackpool North. Therefore there is no justification for having more than one check.
Should the staff have an attitude? No. Is it a problem that it operates a bit differently to some other stations? No. Should passengers comply with this and stop just being awkward because they happen not to like it? Absolutely.
The railway isn't a job creation scheme. It exists to transport passengers, and a handful of freight. The particular direction that the government and industry has taken it, is to offer a high priced and (ostensibly) premium service. So passengers rightly expect high standards, and that includes being treated with a modicum of respect and common sense.
Passengers will quite rightly say "sod that for a game of soldiers" if you unnecessarily inconvenience them, or treat them as if they're naughty children. There is no justification for the way things are done, and that is reason enough why it needs to change.