The answer to your question (as with so many ELL questions) is: It depends on the context.
In my experience, when an English speaker uses a general expression, their intention is not to be rigorous. If I say:
Young people these days don't respect their elders like we did when we were young; they all think we're driveling idiots.
and you reply:
What about young Charlie Bucket? He is always polite and respectful
I might reply:
Then he's the only one. For every Charlie Bucket, there are a dozen Veruca Salts.
I used three "absolute" statements: "young people don't respect their elders," "they all think" and "he's the only one." But in context, it will be understood that I am talking about a general trend among the majority of young people, and I don't consider one counterexample to be relevant.
In the same way, if you say:
A computer is a great way to keep track of your calorie intake
and I respond with:
Well, my computer isn't; it's broken. Has been for years.
I will be seen as nitpicking or quibbling, not as raising a legitimate issue with your point.
This is such a common form of hyperbole that if you do want to express something truly universal, you have to be more explicit.
Every single building on this block is in danger of collapse unless we can get this fire under control.
Unfortunately, native English speakers sometimes use these more explicit constructions, too, as hyperbole. For example, you might well hear a native speaker say:
Literally every other building on this block is a Starbucks.
This is a common form of English hyperbole: saying something in a more definite form than is warranted by the facts.
In general, the takeaway is: don't assume someone is trying to make a definite, absolute, no-exceptions statement unless the speaker makes it expressly clear that he or she is doing so--and not always, even, then.