>>96078872
It's because that Eldar fighting to protect his race is also ready and willing to kill hundreds upon thousands upon millions of innocent men, women, and children of the "lesser races" (which is all of them) in order to protect even a handful of Eldar lives.

Also it's particularly funny that whoever made that image decided to use the Biel-Tan, who are so obsessed with reclaiming the old Eldar empire that they will indiscriminately kill anyone who gets vaguely near old Eldar planets, or even planets that the Eldar never actually colonised but were maybe thinking about getting around to it before the Fall, and happily employ Exterminatus-grade bioweapons that even other Eldar are horrified by to cleanse planets of any and all 'undesirable' life. And all of this slaughter is completely and utterly pointless because the territory of the pre-Fall Eldar empire is such a shitshow that it's literally impossible for Biel-Tan to even make a dent in reclaiming it, and the Eldar as a whole are so few in number that it might not be possible even if every craftworld pooled their resources into making it happen.