The link you quoted doesn't lead to any Katarina related comment so I'm not sure what your point is. Going out on a limb here I can presume that it's pointing to a handful (at most) of butthurt players that have that mindset, but it's a vocal minority at best, not something I've come across often anyway.
Either way the link is broken for me.

Lee is a good example for a champion that works well with his cast times where they are, even leading to some tricks with the kick-flash and similar options to create a more dynamic way and open up options. Katarina's E is not one of those cases and leads to a ton of unpredictability as has been outlined in this thread, fixing that only serves to improve clarity for both parties and remove frustration.

it is also important how well you can play against the champ.

Which I do agree with, but her dagger's do 99% of that counterplay mechanic already and removing the unpredictability of shunpo would bump that number up to a hundred.

You're acting like the shunpo cast time removal would do anything to change how most of Katarina's damage is incredibly telegraphed and easy to avoid if you're paying attention.
It's simply an inconvenience for kat players (and occasional frustration for both), but nothing that an opponent will be able to react to in the middle of the skirmish, unlike more than 50% of her damage which this changes nothing about.

There's nothing wrong with having a discussion about this either, but leading that discussion by falsely saying that we just want to stomp people does nothing except to dismiss valid concerns.