It is a little like saying we all should hold fire on criticizing Cameron, as he made it all the way to Prime Minister.
No it's not - it's nothing
What it is like, is saying we should hold fire on criticising Cameron, if he'd been hypothetically been prime minister for the last 10 years (or more) and hypothetically, yet comprehensively and objectively, showed improvements in the country.
I am not buying it, it is a lame argument.
Well if you're not buying it simply on the rationale you've given, your argument is borked.
The public have no responsibility to judge on anything more than the moment, and it neither undermines nor props up their view to suggest they are not looking at the whole picture.
Most people are blissfully unaware of either the financial performance of G4S, their growth, or their current size.
What most are
aware of, is high-profile, embarrassing, Daily-Wail headline criticisms of the company (in many cases, probably in the main, stemming
from a reasonable basis, but over-egged, because it looks sensationalist; and criticisms stemming from a political bent, regarding their involvement in security and related matters in the UK (as I said, most are blissfully unaware of just how far, internationally, they've spread).
So yes, it does undermine some criticism - because a lot of criticism of G4S is either media stimulated, or political mitherings, and is often from positions of ignorance. I'm far from convinced the same criticisms would be levied if the unwashed truly realised the growth and financial performance of the company (not that I'm overly enamoured with those aspects - but in fairness, is objective metric on how a company is performing at least from a fiscal, or competitive perspective).
Equally, I'm sure many of the shareholders are reasonably satisfied with their performance over time, too - although some will likely be irked by situation(s) with recent acquisitions.