You shouldn't feel the need to apologize. The people who are presumably being paid to act in an editorial capacity for Slashdot are the individuals who should be taking the time to ensure submissions are readable. They're clearly willing and able to edit submissions, yet have rarely shown any inclination toward putting effort into anything beyond adding subjective comments or making questionable changes that result in submitters having to point out what the editors have done.
This has been a problem for as long as I can remember, and while it's excusable from a volunteer-run operation, a paying for-profit operation should be willing to invest in someone willing to do basic proofreading and fact-checking while approving reader-submitted links, favoured weblogger glurge, and Slashvertisements.
Then again, I don't think much of the hypothesis that financial profit is an obligatory motivator for competence, so I'm not surprised that garbled sentences go right by the staff; hiring someone to check the spelling and grammar would cut into profits, after all, and as long as people keep paying for crap, what motivation is there to change?