I've been trying to encourage you to think about this holistically because then you might understand where I'm coming from. How about this: look at the front wall of your house - which bricks is it safe to remove? Which of those directly or indirectly benefit the wall? Maybe those over a doorway or window are obviously important, can't lose those, but what about the others? How many can you safely remove before it no longer fulfills its function? How about if it's a giant game of Jenga? Or a massive construction of scaffolding that's been built and rebuilt again and again over thousands of years and overall is holding up a giant roof but with no clear plan how? Which parts of that are safe to remove?

The bees are an easy win - they do a lot of pollination work, but there are other insects that do that too. But is that all that's important? How about the oxygen you breathe or the nitrogen in the soil that nourishes the plants you eat or the rain that waters them? All these things depend on multiple complex cycles involving things like forests, the health of which depend on many other interconnected webs of life at all levels from mammal to microbe. It's Chesterton's Fence on a grand scale - if you don't know what it does, you really shouldn't remove it until you do know what it does. We're still working that out in many, many cases.

A lot of insects provide food for other animals - kill the insects, and we also kill all the things that feed on them. And there are certainly numerous other natural cycles and systems than those I outlined above (did you know that ocean microbes can seed cloud formation? https://news.agu.org/press-release/bacteria-feeding-on-arcti...) - these are just the ones that come to my mind as someone with an amateur interest in these things; I am, as I said, no expert.

> In general they are gross, numerous, invasive, and they carry diseases.

I understand why you might feel that way but, aside from the first (which is your opinion): the second, as we're discussing, is increasingly not the case; the third is generally only true where humans have transported a species to where it shouldn't be; and the fourth is really only true in very few cases - things like cockroaches and house flies, but even these fulfill important roles breaking down organic matter that would otherwise litter the surface of the planet, and thus returning nutrients into the soil, keeping it fertile. Cockroaches etc. are only a disease risk when they intersect with us, find a huge source of waste, and multiply excessively - and in those cases of course we have to deal with them.

> I still do not see why we should protect the insects that are in the city as they do not bring us any benefit.

An obvious reason that comes to mind is that cities as a black hole for insects act to decrease the overall population by simple diffusion.