Barrie England, writing at Caxton on the imply/infer issue,* quotes and comments on the entry on the matter in Merriam-Webster's Dictionary of English Usage

"Careful writers will still, no doubt, maintain the distinction, but criticism of the use in speech and, these days, in informal prose, of personal infer where others might prefer imply is more likely to be a sign of bigotry than of learning. MWDEU describes one of the objections to personal infer as social in that ‘the personal infer has been associated with uncultured persons.’ That might be said of many usages in the Negative Canon. If so, it ignores the fact that the language of ‘uncultured persons’ is just as capable of serving a particular communicative purpose at a particular time and in a particular place as that of the culturally sophisticated."

Let's try to be clear about who we are and what we're about. 

Unless you object strenuously, I am enrolling myself among the culturally sophisticated. Two university degrees. More than thirty-three years as an editor, upholding the standards of formal written English. My personal predilection is for the speech and writing of cultured persons. Maintaining distinctions of usage is both my job and my personal preference. 

The job involves a straddle. Since newspapers attempt to reach the broadest possible audience, the texts I edit are intended to be comprehensible to the uncultured reader without exciting the contempt of the cultured one. The working assumption is that the distinctions of usage we maintain will pass the uncultured reader unnoticed while appreciated by the cultured one. 

This is as neutral as I can make it, but it is impossible to ignore the social aspects and overtones of language, particularly once loaded words like cultured and uncultured, sophisticated and unsophisticated are dropped into the conversation. This is where I have to part company with the peeververein, who you would ordinarily think are my natural allies. 

The mistakes the hard-shell sticklers make is to treat standard written English as the language, with everything else some inferior variant. They are mistaken. Among the many Englishes, spoken and written, standard written English is merely English as she is edited. As Mr. England quite rightly points out, "the language of ‘uncultured persons’ is just as capable of serving a particular communicative purpose at a particular time and in a particular place as that of the culturally sophisticated." The peevers can't let that go. From their mastery of a set of conventions of written English flows their social status. From that elevation they pour out contempt on people they dismiss as ignorant and barbaric. But these pretensions are no more substantial than the vulgar belief that someone who has amassed a pile of money is worthier then people with less. 

I don't spend time condemning people who use imply and infer interchangeably in speech, or who say irregardless or use double negatives. I reserve my ample store of scorn for people who ought to know better: professional writers who haven't bothered to learn the tools of the trade, lazy writers who waste the reader's time, purveyors of bombast, self-proclaimed authorities on language who hold to shibboleths and zombie rules in the face of all evidence and argument, snobs. 

If they were genuinely cultured, they would behave better. 

  

*No, I am not going there today. Your're welcome to read Mr. England's remarks. If you are a glutton for information, you can read what Mark Liberman says at Language Log about four centuries of blurred usage