/*Less Rita Skeeter more Dumbledore*/
There needs to be some revision to the Karkus article because it sounds like it was written by Rita Skeeter. JKR said that, when in doubt, DD was usually right - so will try to tease what DD told Hagrid from the prejudice he gleaned from others. There has been a lot of propaganda in the wizarding world and Hagrid has been told all his life that giants were violent by people, such as Fudge (whom DD labled prejudice) and Rita Skeeter.
As far as going extinct killing each other off, the same can be said for muggles and wizards - there were 3 wizarding wars in DD's lifetime that we know about! On the other computer is a quote about Grawp's eating habits, but that is probably the real reason that giants (like elephants and rhinos) don't do well in cramped spaces with scarse resources. Despite Hagrid's constant fear that violence would break out, Karkus's bunch seemed quite docile - even after they were attacked in their sleep, they were more apt to be hiding from the fighting than wishing to participate in it.
And one doesn't have to mention lazy twice. Some of these giants seem quite educated despite their meagre circumstances - being able to speak more than one language, when Hagrid barely speaks one.
The article omits the most important thing about Karkus - that he had both heard of Dumbledore, though highly of the wizard an why he thought highly of Dumbledore. The real reason the Death Eaters instigated a coup was to get rid of the Dumbledore friendly gurg and install their own puppet dictator / Death Eater friendly gurg. Note that the Macnair was casing out the caves for Golomath and providing him with information. If Golgomath's bunch were going cave to cave, they wouldn't know what they were walking into - but Macnair's information they would.
p. 382 (OOTP 20) – ‘… At night, when the giants were sleepin’ an’ we wanted ter be creepin’ inter the caves, Macnair an’ the other one were sneakin’ round the mountains lookin’ fer …’
p. 503 (GOF 29) – ‘I no more suspect Madame Maxime than Hagrid,’ said Dumbledore, just as calmly. ‘I think it possible that it is you who are prejudiced, Cornelius.’
p. 614 (GOF 36) – ‘Envoys to the giants?’ Fudge shrieked, finding his tongue again. ‘What madness is this?’ ‘Extend them the hand of friendship, now, before it is too late,’ said Dumbledore, ‘or Voldemort will persuade them, as he did before, that he alone among wizards will give them their rights and freedom!’
p. 374 (GOF 23) – ‘Well, they were dying out anyway, and then loads got themselves killed by Aurors. There’re supposed to be giants abroad, though … they hid out in mountains mostly …’
p. 377 (OOTP 20) – ‘… Bu’ they’ve bin dyin’ out fer ages. Wizards killed a few, o’course, …’
p. 378 (OOTP 20) – ‘… They’re not made ter live bunched up together like tha’. Dumbledore says it’s our fault, it was the wizards who forced ’em to go an’ made ’em live a good long way from us an’ they had no choice bu’ ter stick together fer their own protection.’
pp. 378-379 (OOTP 20) – ‘… we did what Dumbledore told us ter do, which was ter hold our gift up high an’ keep our eyes on the Gurg an’ ignore the others. So tha’s what we did. An’ the rest of ’em went quiet an’ watched us pass an’ we got right up ter Karkus’s feet an’ we bowed an’ put our present down in front o’ him.’
p. 379 (OOTP 20) – ‘And what did Karkus say?’ asked Harry eagerly. ‘Nothin’.’ Said Hagrid. ‘Didn’t speak English.’ / ‘… Karkus knew enough to yell fer a couple o’ giants who knew our lingo an’ they translated fer us.’
p. 379 (OOTP 20) – ‘Dumbledore wanted us ter take it very slow,’ said Hagrid. ‘Let ’em see we kept our promises. …’
p. 380 (OOTP 20) – ‘… He heard o’ Dumbledore, heard he’d argued against the killin’ o’ the last giants in Britain. …’
p. 380 (OOTP 20) – ‘Well, like I say, they’re not meant ter live together, giants,’ said Hagrid sadly. ‘Not in big groups like that. …’