You're not arguing anything. You're saying "I think something else can be good too".
Until you literally give an actual engineering (comparison of performance/reliablity/etc) reason that hypergolics are the wrong choice to make, this is effectively saying that "something should be different because I think so"
> Until you literally give an actual engineering (comparison of performance/reliablity/etc) reason that hypergolics are the wrong choice to make, this is effectively saying that "something should be different because I think so"
As with many discussions, we talk here mostly qualitative differences. Quantitative differences are harder to get by - for example, back of the envelop calculation says that 30 kg of peroxide in Soyuz landing capsule could be, roughly, replaced with 15 kg of hydrazine, so you'd have a 15 kg mass saving here, but in general actual engineering calculations are harder. I wish they wouldn't be such.
Given those very crude estimations and the practice, which shows there are no big unforeseen problems, we have a valid arguments for the alternative. It's an engineering argument, an estimation and not necessarily full calculations, and it's not effectively an arbitrary opinion. You may finally decide the issue using hard numbers, but since we don't have them now, the question stands.
Until you literally give an actual engineering (comparison of performance/reliablity/etc) reason that hypergolics are the wrong choice to make, this is effectively saying that "something should be different because I think so"