That's much worse than I thought. The Web is not a Google or Apple product, and your product's design shouldn't change based on which browser you use. That entirely misses the point of the open WWW. It's a terrible idea to build things in that way.
This is a feature of Ionic you’re free to disable but many users like very much. It is more widely used for apps running in the App Store that want to map to iOS and Android UI standards for each platform.
We also pride ourselves on making Ionic easily brandable so the platform standards provide a good base you can easily remix to make it look quite different.
Sorry to disagree, but Material Design itself lacks aesthetic restraint and has accessibility problems with the constant flashing and animation, but that's another conversation.
Edit: I'm talking about the browser, not apps (though I don't like MD there either). I mean that websites shouldn't change their design based on the company that makes the web browser.
There's a battle between some of the large tech companies for appification of the Web at the moment, and that way of thinking is a trap.
A company shouldn't design its website with Google or Apple's visual branding as if it were locked into a closed platform. It also appears to be a problem with things like Flutter, though I haven't looked closely.
I assume you have never tried it.
Having that as a default means that many people will implement it.
Some apps are web technologically, but are local tools by purpose; that's where blending it could be beneficial for the user.