Because it is just a complaint with nothing really to offer. Your example is probably the worst one to use too. Your solution is flawed too. -10% from a specific class is really a bad idea for those who really do not need it.
am sure they will be picked just as much
This is not a good enough reason to justify a massive nerf to an entire class. What if I said:
"Poke champions poke too often. So make all of their CDs 10% longer. Just 10%. I'm sure they will still be picked. I ask this because Lux is using her E too much because runes give free 5% CDR."
See not really a solid argument or any real reason to justify the claim. It is simply 1 instance with 1 champion doing what they are actually meant to be doing. That is your entire reasoning behind this post. That is why the downvotes are happening.
Not to say your post is a bad thought (thought I do not agree with it) but this is not enough to have a discussion with. Not a lot of the issues() are flushed out. Maybe find many examples of multiple ADCs doing this. A clip is really good. Then you have an argument.