Well the Bijuu hated humans because they believed they were only capable of war and that the tailed beasts were only tools and weapons of the humans.
Ashura and Indra started the war of all wars, pretty much in a fight over power.
It might've not meant anything to Kurama to say Naruto reminded him of Ashura, in fact, I bet Hashirama reminded Kurama more of Ashura, which is why Hashirama was included in that whole "Humans are all the same" flashback.
There's ways to explain it, but it is odd I'll admit. Especially when the Bijuu all agreed that Naruto was the successor, which should have instantly reminded them of Ashura. The explanation is going to be weird when Kishi gets to it :| but there's...."explanations"