Because its everywhere in schools at the moment.
DD's bubble popped for the 4th time on Tuesday. She has to isolate until after the term ends. She's year 6, so Tuesday was her last day of primary.
She's missing all the end of term activities and all the saying goodbye.
If I'd pulled her out, she'd still have missed them, but she wouldn't ALSO have missed all the last classes for her hobbies, seeing her cousin, being able to go out in the great weather we're having, the 1st of her planned holiday activities, seeing her friends etc etc, and we wouldn't be struggling like mad with cancelling our plans for the weekend.
She'll have done 40 days stuck in a house with postage stamp back yard since September, plus the limitations of the lockdowns. Her Oct 1/2 term was a write off, because she was isolating, Christmas was under the rules change, so we did nothing and saw no-one, her birthday was in lockdown, Feb 1/2 term was in lockdown, Easter was spent isolating, and she's now isolated twice since May 1/2 term.
We're northwest, so we were Tier 3 for most of last year, as well. In real terms, restrictions on her hobbies and on seeing her friends never happened here at all.
This summer holiday is/was the first chance she's had since March 20 to be an unrestricted child... and she's starting it in isolation.
It's enough to stress anyone, and I don't blame any patent for not wanting to risk the same for themselves and their kids.