Inline CSS and inline JS works differently, depends how it’s enqueued into the theme.
If it’s enqueued as a child of some css or js file, it will be minified but if it’s printed directly on the header it won’t be (impossible to hook into those).
If your inline css is a child of some other css file, it will be minified.
Inline JS is never minified because “line breaks matters” in javascript and not all white space can be trimmed… for that reason inline js is always disabled, but it doesn’t matter because this doesn’t affect your score and the savings is probably a few bytes only.
That’s also the reason why minifying twice the same js file usually breaks it, most notably the jquery.js file shipped with wordpress (it cannot be minified again or breaks).
The option to disable minification also exists because of this… sometimes it works when merging but not after merging + minification. Some times authors don’t ship minified versions properly renamed to min.js and those end up minified again thus breaking things.
It would be perfect if all authors follow the standard wordpress api usage, it would avoid a lot of workarounds I’ve been adding to cater to all of them (in your case, html comments should not be used on html for javascript things… but those are ok inside script tags)
