I was very careful to say "in this context": the context of pronunciation in spoken English. If you regard accents or dialects as legitimate ("not sloppy"), I don't see how you can regard sizeable amounts of people speaking a certain way within those accents as "sloppy"/improper.

Essentially, I suppose it amounts to this: if one person speaks a certain way different from the norm, you could call it sloppy; but if thousands of people do, it's too late, it's English.

Thousands of working-class British people routinely say "dem" rather than "those". Are they sloppy? Are they wrong? If that's how their parents speak and their friends speak, you really call it inarticulacy.

My boss often describes something as "a bit of damp squid". We all find this highly amusing at work, though we've never corrected him. However, if thousands of people routinely made the same mistake, the phrase "a damp squib" would quickly become archaic, and it would cease to be a mistake, becoming just another of those quirky phrases. I often think these things are a shame. But that's language for you. The changing use of the word "impacted" is a good example.