You're right, this objection is not relevant in general.
But in the situation we talk about, having 20 % more performance requires you to choose a fork that can came with it's own limitation. It's definitely not free.
This trade of makes the point about the language choice relevant.
My gut feeling is that Python is just not safe or static enough to ever be worth trying to compete with (say) C++ with. Python sure is easy but I think the asymptotic cost of using it for a big project (in my hands at least) is just not worth it.
I like Python's syntax quite a bit but I feel bad watching people learn to program using it - partly because it's an oddly low-level language (It's closer to being C than Haskell) and there's no compiler to stop you shooting yourself in the foot (If I write something fundamentally unsound I want to know about it now not when the process has been running all day)
It's simple, really. They're concerned about the trade-offs.
And more importantly, your original question isn't asking about forks, specifically. It was asking why someone might oppose performance work.
But it's compatible. It's a drop-in replacement.
Moreover, you continue to cherry pick, neglecting the other arguments you’ve been presented. It sounds like you’ve already made up your mind about this.
Presumably because they see it as effort that could be better applied elsewhere.
I don't know that I agree, but I can understand the viewpoint.
Right - but if you can get that with better performance that's good isn't it?
I don't get why people object to performance work on languages not intended for performance.