If your reader concerned about the use of “sucks” worries that he sounds like a queer studies major, then his worries are founded. By his logic, we should think about ceasing to use “jerk” (from the fuller “don’t be such a jerk-off!”). The British “tosser” has to go too. So does “ass-kisser”, which seems a perfect description of someone who sucks up to the boss – but ‘”suck up” probably has to go too, as well as “brown-noser” obviously. More generally, we should probably consider dropping “fuck” and its infinite permutations (certainly “this fucking sucks”), for we don’t want to suggest that there is anything wrong with fucking. Or are we allowed to keep “motherfucker” because we still disapprove of incest? What about “asshole” – isn’t that just a body part like all the others? Does the use of “asshole” as an insult display a certain puritanical revulsion at the body? I could go on indefinitely …

Another:

I’ve never considered “sucks” – as in “this broccoli sucks” – to be referring to a sex act. To me, it means the thing in question sucks the joy out of the situation. “This broccoli sucks the joy out of eating.”  Nothing derogatory about it.  Maybe it’s a guy thing to automatically jump to the sexual?

Another:

“Sucks” can actually be traced back to a phrase common among farmers during the Great Depression, who would remark that something “sucks hind tit.” This is because pigs, dogs, etc feed from their mothers, and from the perspective of the farmers the rear one was the least desirable (I’m not sure if there’s a reason for that, or just the general proximity to the rear end of the animal).  From there, the phrase was shortened and has certainly be considered low and offensive for a long time.  But that might speak more to the dirty minds of the censors than those who actually came up with the term.

Several more:

A quick Google search reveals that there is an ongoing debate as to the origin of the word.

According to the Urban Dictionary, it comes from jazz musicians.  A great musician on the horn could really “blow.”  Someone who was horrible sounded like they were “sucking” on the horn.  A recent defense of the word on Slate offered other sources, like farmers using the phrase “sucks hind teat” or British schoolchildren using “sucks to you” with no sexual connotation. And even if it does have a sexual origin, who cares at this point?  Your reader should just suck it up and let it be.

Another:

Back when I was a kid, I was able to convince my very skeptical father that I should be allowed to wear a “Boston Sucks” T-shirt (I’ve been a lifelong Yankees fan) because it was plausibly “Boston Sucks Eggs” rather than “Boston Sucks Shit”, which was how he interpreted it.  I seem to remember “Go suck eggs” was a relatively common insult (the functional if less inflammatory equivalent of “Eat shit and die”), even showing up in cartoons. I’m pretty convinced that that’s the etymological line that leads to everything sucking these days.

Another:

In 1986 or ’87, when I was a naive 6th-grader (maybe 7th), on the first day of class my science teacher laid down the rules.  She was a tough, progressive, feminist, four-Swatch-on-one-wrist-wearing bitch. Not butch, but maybe a lesbian – I don’t know.  I liked her right away.  In addition to saying things like, “This classroom is not a democracy, it is a monarchy, and I am the monarch,” she also said:

I will not tolerate the phrase “you suck.”  Do you know where that term comes from?  It comes from the root word “cocksucker” meaning one who sucks cocks, and in no instance is it appropriate in my classroom.  It is derogatory and offensive and will not be tolerated.

Holy Handjobbers!  I’d never heard such a thing, but boy did it stick with me.

Another:

So we have a word that may or may not have originally referred to a homosexual act and that is usually not used to refer to a homosexual act. I fail to see the problem. Etymology is not destiny. Just because the origin of the term is fellatio does not mean that’s what it means now.  Lots of words are secretly vulgar. “Pencil” shares a root with “penis”. “Avocado” is an Aztec word meaning “testicle”. “Scumbag” means condom. I will give you the pleasure of looking up the etymology of “pumpernickel” on your own. Words change. Usage matters more than history.

(I can’t believe I just spent half an hour researching “suck”. This is why I read your blog.)