> The gov.uk website completely eschews JavaScript at some usability cost

I would imagine this was mostly driven by accessibility requirements more so than some ideological rigidity.

Unfortunately, some people view accessibility as an ideology.

Perhaps, but, taking the example provided, Gov.uk deals with population scale products funded by taxpayers and which may be exclusively digital. Accessibility as an ideology makes sense in this context, and, I would argue, is morally correct.

It’s easy to dismiss the genuine needs of someone else if one’s not impacted though.

Ideology or not, exclusion does not help.

a little bit of the right kind of JavaScript helps accessibility, so it's clearly not