Fair enough if you don't think it's worth it.
Paying more than a thousand pounds, completing several tests and undergoing a bureaucratic process that's like a first passport application on steroids -- for the privilege of continuing to live securely in a country where you've already been residing and paying taxes for years? Reminds me of that Peep Show quote about replacing the boiler:
Surely the least enjoyable way to spend a thousand pounds... I have spent a cool grand on acquiring the resumption of an equitable temperature.
Gaining citizenship is, and should be, a big deal. But as long as we were in the EU, people within the union could move and settle with relative security without this, and they've built up careers and raised families under the assumption this right would continue. Now that's all up for change. Fine if you think that's good, but you don't need to act like those directly affected should make no fuss whatsoever and cheerfully cough up a grand if they want to stay.