Every culture has a way of discussing and resolving disagreements. Some are noisier and some are calmer. Some cultures do this dance with "apparent" disrespect, with forceful exchanges, some with calmer and tidier demeanor.

Japanese are the latter. There's a polite dance of disagreement. Every side listens others with respect (with respect to the process even if they don't respect the others) and answer politely yet firmly.

This comment smells like there's already some disagreement under this, and none of them have been listened and they are steamrolled with the new workflow.

Implying "Hey you're overreacting, let us convince you" doesn't help on top of it.

Politely say "I don't care what you think but I won't change anything" is perfectly fine in Japanese culture. Taking an issue privately instead of showing disagreements in public is also perfectly fine for Japanese people.

The issue has nothing to do with Japanese culture, but with how you work with a community of volunteers over the web. "Let's jump on a call" is what you say to a coworker, not to a volunteer in an online community.