They said that dragons are regular creatures.
Then wouldn't they *oppose* to the fact some(one/thing) wants to "eat the world" (Implied to physically eating, as mentioned many times on the forum. True meaning and intentions are unclear. Metaphorically or otherwise) that would likely result in them being killed? If that were the case then there would or should certainly be some willing to lend you their aid WITHOUT you murdering their brothers/sisters etc.
Regular creatures again implies that they are disposable monsters and not worth concerning over whether they live, die, or go extinct or whatever. Dragons + Humans/Elves vs Dragons would be interesting (To me anyway...) where the dragons siding with humans (Like in Runes of Magic and Warcraft) may or may not actually AID you directly ...
Also how can you not justify slaying a dragon when it's ransacking a local village murdering innocent people? :confused:
How can you justify plowing down their homes to make room for a bunch of cows and then expecting them to let you continue doing so? (Non-elder scrolls example most likely... But still)
Sure if your life is on the line like that anyone would attack one. Of course, if the creature is capable of intelligent thought on par with humans and elves, one could try reasoning with him or her. I am more talking about their only purpose in the game is to provide something to kill, attack things, and overall just be in your way.