I am not disputing that languages change over time (I am not touching that last one), but that does not mean that pointing out the inconsistencies of new developments are invalid.
It has a regular usage pattern and regular semantic understanding and is tied to a specific region that has its own patterns. It seems to come down to which regional variation is assigned more "prestige" than the others. I happen to think that the lack of a specific second-person plural in most of the other English dialects is deplorable, but that's just me

Illusions fall like the husk of a fruit, one after another, and the fruit is experience. - Narrator, Sylvie
Je suis méchant.
Je suis méchant.

From David Mitchell: Dear America
20/05/2010 03:16:38 PM
- 792 Views
As a non-native Eng-spleaking person...
20/05/2010 03:32:14 PM
- 487 Views
"Could care less is" a personal peeve of mine, too.
20/05/2010 03:43:08 PM
- 477 Views
Mine also
20/05/2010 04:08:23 PM
- 608 Views
Oh, and for the record: the use of "table" as a verb in politics still confuses me for about 5 sec.
20/05/2010 04:38:35 PM
- 486 Views
What a grating accent
20/05/2010 10:41:38 PM
- 468 Views

what grammatical conventions?
20/05/2010 11:11:10 PM
- 450 Views
Subjunctive, reflective pronouns, things like that
20/05/2010 11:26:09 PM
- 464 Views
His main two points had nothing to do with all that, though...
20/05/2010 11:39:28 PM
- 575 Views
I know. I just merely said I disliked the accent and that the divergent dialects were just that
20/05/2010 11:59:25 PM
- 494 Views
How does that apply at all?
20/05/2010 11:43:49 PM
- 470 Views
Different rules for different dialects
21/05/2010 12:03:31 AM
- 583 Views
.... dialects?
21/05/2010 12:06:03 AM
- 544 Views
Yes, dialects
21/05/2010 12:20:09 AM
- 544 Views
Re: Yes, dialects
21/05/2010 12:24:25 AM
- 430 Views
Perhaps
21/05/2010 12:54:49 AM
- 526 Views
Re: Perhaps
21/05/2010 12:56:18 AM
- 457 Views
It really depends
21/05/2010 01:03:13 AM
- 635 Views
Re: It really depends
21/05/2010 01:05:21 AM
- 591 Views
But it isn't inconsistent
21/05/2010 01:14:32 AM
- 438 Views