To unpack some of this, you must understand what VS is, and why it's bad.

The idea is that by signalling virtue for something you don't really care about (or care about less that you imply) you are: misrepresenting your character, and reaping the benefit of untrue positive assumptions, and by extension, building illegitimate trust/reputation.

Per the phrase "when a metric becomes a benchmark, it ceases to be a useful metric", if corps or individuals benefit from certain virtuous signal, it ceases to be an useful metric of virtue.

> despite this particular incident, there are many laudable contributions to social causes that Google has supported over the years

Did Google derive any positive benefit from those contributions aside from the benefit to the cause itself? e.g. positive reputation. It is precisely that which results in accusations of VS: Even immoral corps benefit from social-cause PR, and the difference is in the details. e.g. you judge a person not by how they treat their friends (or boss), but by how they treat their waiter.

> The idea that professing some sort of belief which one acknowledges as "good" is nonetheless somehow "bad"

This is an oversimplification. Giving to charity is good, even if done for ingenuine reasons, but a corp should not be considered generally virtuous in that case i.e. no virtue beyond that contribution should be assumed. Chemotherapy has a devastating affect on the body, yet utilised to treat cancer; It is "good" because the overall context is considered, having cancer is still bad. The world is more nuanced than everything fitting into two categories, free of context.

> It is still PR for the good cause. When it's convincing, people will act on it.

I agree, Virtue-signally may still have its benefits. That doesn't change what it is though. I think you need to look at the context to decide whether it matters or not.

> even if they have been the most cynical liars, their statements will have the effect of setting expectations for them and their industry peers

It might, but it could also lead to the precedent whereby corps make hollow statements that they don't need to live up to. The precedent is that "unlimited" (as in broadband, storage) doesn't actually mean unlimited, so why can't "environmentally-friendly" be expected to mean little?

> Are we to believe they have any actual interest in, say, increased diversity

But they don't have to, unless they are accusing someone/thing of VS to imply their own virtue. If I don't believe you care about X, I don't need to care about X myself to make that accusation. There are, however, cases where it does matter, but again it depends on context, and why people think it relevant to make that accusation. The opinion I seek to counter, however Is that a persons true motivations are either always, or never relevant; or that they can always be known.

> Instead, it's used by these people because their real opinion just cannot be openly stated in polite company any longer

I could just as well make the same paranoid argument: "people who complain about the phrase 'virtue-signalling' do so because they are virtue signallers themselves with more sinister motivations that they cannot state upfront, or in 'polite company'"

This is just an unsupported bad-faith interpretation of your political opposites. How do you know what the motivations of the "political right" are? There are plenty accusative phrases used mostly by the political left - are those invalid by the same reasoning?