Clearly some do bert, or at the least don't care provided it's somebody else's child. Otherwise there wouldn't be so many declaring the current comprehensive system is so much fairer, when it's actually not.
If I said the grammar system was fair, because my dd scored highly with no more than the cost of some practice papers, a few hours familiarising herself with the content and me timing a practice paper, and therefore got a school that suits her needs, you and a dozen other posters would all (quite rightly) point out that doesn't make the system fair, or better for everyone. fresh doing exactly the same thing, but using affluence instead of ability, has had only a small number of people point out that her situation doesn't make the comprehensive system fair for everyone.
If you did a poll of mumsnet, asking who wants to abolish grammars, I bet you'd get far more support than you would for lottery admissions.
The latter won't ever win votes because the mc stand to lose, and therefore won't ever happen. Ditto for reallocating funding so schools full of easy mc dc get less than schools with more difficult cohorts. Whereas introducing fair criteria for grammar entrance could be done without outrage, because the same mc person can't object unless they are willing to say 'my dc isn't able enough to compete on a level playing field'. Which won't happen.
The only 'easy' step to reducing some unfairness in comprehensives Is banning religious criteria, but that won't be enough in itself.
Allowing a few more grammars, and opening up the access isn't the ideal solution, nor what I'd actually do if I was in charge. But until the comprehensive system is actually fair, the odd grammar won't make it any worse for those at the losing end of either system, and at least offers a lifeline to some who have no chance of a suitable education otherwise.