Whether or not Google deprecating XSLT is a “political” decision (in authors words), I don’t know that I know for sure, but I can imagine running the Chrome project and steering for more simplicity.
Yes, it's a problem that Chrome has too much market share, but XSLT's removal isn't a good demonstration of that.
[1] Yes, I already know about your one European law example that you only found out exists because of this drama.
But it ultimately doesn't matter either way. A major selling point/part of the "contract" the web platform has with web developers is backwards compatibility. If you make a web site which only relies on web standards (i.e. not vendor specific features or 3rd party plugins), you can/could expect it to keep working forever. Browser makers choosing to break that "contract" is bad for the internet regardless of how popular XSLT is.
Oh, and as the linked article points out, the attack surface concerns are obviously bad faith. The polyfil means browser makers could choose to sandbox it in a way that would be no less robust than their existing JS runtime.
No, this is wrong.
Maintaining XSLT support has a cost, both in providing an attack surface and in employee-hours just to keep it around. Suppose it is not used at all, then removing it would be unquestionably good, as cost & attack surface would go down with no downside. Obviously it's not the case that it has zero usage, so it comes down to a cost-benefit question, which is where popularity comes in.
And no, it really isn't a cost benefit question. Or if you'd prefer, the _indirect_ costs of breaking backwards compatibility are much higher than the _direct_ cost. As it stood, as a web developer you only needed to make sure that your code followed standards and it would continue to work. If the browser makers can decide to depriciate those standards, developers have to instead attempt to divine whether or not the features they want to use will remain popular (or rather, whether browser makers will continue to _think_ they're popular, which is very much not the same thing).
I don't see any evidence supporting your assertion of them acting in bad faith, so I didn't reply to the point. Sandboxes are not perfect, they don't transform insecure code into perfectly secure code. And as I've said, it's not only a security risk, it's also a maintenance cost: maintaining the integration, building the software, and testing it, is not free either.
It's fine to disagree on the costs/benefits and where you draw the line on supporting the removal, but fundamentally it's just a cost-benefit question. I don't see anyone at Chrome acting in bad faith with regards to XSLT removal. The drama here is really overblown.
> the _indirect_ costs of breaking backwards compatibility are much higher than the _direct_ cost ... If the browser makers can decide to deprecate those standards, developers have to instead attempt to divine whether or not the features they want to use will remain popular.
This seems overly dramatic. It's a small streamlining of an important software, by removing an expensive feature with almost zero usage. No one actually cares about this feature, they just like screaming at Google. (To be fair, so do I! But you gotta pick your battles, and this particular argument is a dud.)
If browser makers had simply said that maintaining all the web standards was too much work and they were opting to depreciate parts of it, I'd likely still object but I wouldn't be calling it bad faith. As it stands however, they and their defenders continue to cite alleged security problems as one of if not the primary reason to remove XSLT. This alleged security justification is a lie. We know it's a lie because there exists a trivial way to virtually completely remove the security burden presented by XSLT to browser maintainers without depreciating it, and the chrome team is well aware of this option. There is no significant difference in security between "shipping an existing polyfil which implements XSLT from inside the browser's sandbox instead of outside it" and "removing all support for XSLT", so security isn't the reason they're very deliberately choosing the former over the latter.
> This seems overly dramatic. It's a small streamlining of an important software, by removing an expensive feature with almost zero usage
This isn't a counter argument, you've just repeated your point that XSLT (allegedly) isn't sufficiently well used to justify maintaining it, ignoring the fact that said tradeoff being made by browser maintainers in the first place is a problem.