Okay SOME Dragons make me sad to kill them...
Mirmulnir is a notable example, His name means Allegiance Strong Hunt and theses are the lines he says translated And some he actually says in english (Got them from the Wiki)
"Krif krin. Pruzah!" [Fight couragously. Good!]
"Brit grah. [Beautiful battle.] I had forgotten what fine sport you mortals can provide!"
"You are brave. Balaan hokoron. [Balaan (?) enemies.] Your defeat brings me honor."
And of course Paarthurnax Which you can of course spare! This also Brings me to the point that the Blades are monsters! They want to basically Destroy the race of dragons! There genocidal Maniacs!
Anyone else think the same way

Killing dragons, murder? Pah, you fools are all the same, you dance around your scaly little birebreathing lizards just because they are powerful. They are monsters, creatures of horrible power, and mind! Look at what they did to mankind, what with the dragoncults and such. All dragons deserve to die, and I am quite glad I beat Paarthunax's face in.

there are some dragons, in the lore, that sided against Alduin.

not all dragons are evil and should die.

the blades should be roasted on a slow moving spit.

if it wasn't for Paarthurnax human's would have stood no chance at sending Alduin to his death ( i say it like this to stop many spoilers )

I can't see how a dragon enjoying fighting deserves to live when others not. Paarthumax and other dragons not aligned with Alduin are another question.