I read a comment today in which it was stated that the use of ‘they’ as a gender-neutral pronoun, as in " A person who eats only what they can for for nothing", is normal usage now.
It went on to say that Americans tend to object to this usage, and I wondered if that was really the case.
Based solely on my personal experience, I’d say it’s used quite commonly, and it still sets my ear on edge.
I think it’s becoming more and more acceptable. People who aren’t averse to evolving language know that’s just the way it’s going. People who are averse to evolving language have largely been educated that that’s the way it used to be, thanks to grammar websites. People who don’t give two shakes either way don’t factor. So that leaves a group of people who think their fourth grade teacher was the be all end all of grammar education, and the way they said it while growing up was the One Right Way, and anything before or after them is Wrong. Luckily, those people die off every day. 
The Chicago Manual still recommends one avoid the pronoun issue if *possible *by re-writing the sentence to allow for greater specificity or the use of a plural they…but it’s not (and never has been) verbotten to use they as a singular.
In the example that you provided, “A person who eats only what they can for nothing” it seems (and sounds) perfectly normal, IMHO. But that’s just me. 
How else would you make that statement? 
ETA: I assume you didn’t really mean to type ‘for’ twice. 
“A person who eats only that which can be obtained for nothing…”
“People who eat only what they can for nothing…”
“A person who eats only what he can for nothing…” <—pisses off feminists.
“A person who eats only what he or she can for nothing…” <—pisses off anyone who loves beautiful language
“One who eats only what one can for nothing”
Although the example sentence is a little weird.
Hell, I use that all the time. I mostly use when what I’m talking about definitely has a gender yet for whatever reason I don’t want that as part of the discussion. So for example if I was writing up a review of an interview on Glassdoor I could use “they” because I’d prefer not to reveal the gender of a particular person I interviewed with. I mean English does have a neutral pronoun, it, but it just sounds far worse to refer to a person as “it”.
It as been normal usage pretty much forever, longer, certainly, than there has been a vocal feminist movement to object to the generic “he” (so it is not really about that).
It is not Americans who object to it, it is Grammar Nazis (American or otherwise) who want to privilege what they see as the “logic” of the language (although there is nothing logical about languages) over not only normal, common usage, but also communicative effectiveness and euphony.
Well yes, I am a grammar Nazi, but it doesn’t seem so farfetched to see that “they” is plural. However, I don’t object to the use of “they” as singular in speech. I do want more “proper” usage in writing.
Title edited to better indicate subject.
Colibri
General Questions Moderator
If it’s proper enough for this hack, it’s proper enough for me. 
[QUOTE=William Shakespeare, A Comedy of Errors, Act IV, Scene 3]
There’s not a man I meet but doth salute me
As if I were their well-acquainted friend
[/QUOTE]
Many standard references allow for the use of singular they/their (although this is not universal):
That usage is not remotely new.
There have been numerous other threads on the SDMB concerning this exact topic. Cecil has mentioned it as well. Feel free to consult those sources.
Actually, the singular they has been common since the middle ages. Chaucer not only used it, he also had characters who “axed” questions.
One can hardly hold Chaucer up as a good example of modern language use:
‘‘Love is a thyng as any spirit free.
Wommen, of kynde, desiren libertee,
And nat to been constreyned as a thral;
And so doon men, if I sooth seyen shal.’’
Way to miss the point, Bob.
Incidentally, here are a few other threads about this exact topic on the SDMB. The argument has popped up tangentially in other threads as well.
Here is our great and most knowledgeable master’s take on the “issue.”
And here is what “Common Errors in English Usage” has to say about this topic:
I find that sometimes using singular they, them, or their feels natural, and sometimes it sounds wrong. I haven’t spent time trying to determine what criteria my brain is using to make the distinction, though.
I find I get different bees in my bonnet as I get older. At one time I would have railed about a split infinitive, but not these days. There are some things that annoy me - the grocer’s apostrophe is the worst, but I have a new pet hate now - ‘for free’. It’s everywhere and it really annoys me beyond rationality. What’s wrong with just ‘free’?
Singular “they” sure sounds smoother than gender neutral pronouns like “sie”, and at the same time accomplishes not addressing the gender of the person.
For completeness perhaps we should all agree on:
“A person who eats only what he (if he has a penis and is cisgender) or she (if she has a vagina and is cisgender) or he (if he has a vagina and is transgender) or she (if she has a penis and is transgender) or sie (if that’s what the person prefers and the person has hip friends) or they (if the person doesn’t want to steer the conversation toward genitals but also doesn’t want to make anything sound cumbersome) can for for nothing.”