It's implying that X matters to Zero as much as the reverse, when there's really no indication of such even in MMZ.
the entire plotline of mega man zero in my personal view was zero continuing as always to fulfill x's desire of a world where reploids and humans can live in peace. his big speech at the end of z4, even. "
I have always only fought for the people I believe in." consistently, the only thing zero has ever fought for was the maverick hunters, which doesn't make much sense beyond that line if you think he didn't believe in x's ideals. why would zero continue to fight in the elf wars? why would he fight for the resistance?
none of those things are his personal ideals. zero is nothing
but a reflection of what other people want him to do. it was x's dream by proxy of doctor light, as stated in the x2 ending, that reploids and humans live together. that's the goal for elysium as well in the X ending of X5 (or was it 6?), and obviously as the series progressed into ZX, they kind of get closer to x's goal of enabling them to live in harmony, which i interpret to be the purpose of the reploids gaining lifespans and humans getting enhancements like reploids, to equalize the two races. and then, sometime between zx and legends, elysium itself was founded and was apparently a perfect, but sterile, world. the master being the last genetic human and the carbons being an obvious evolution of reploids to make them 'fully human', but the creators knew that they weren't really human.
maybe that's just retarded, or some dev said that this is not true, but i'm not sure that capcom even cares about the timelines and what any poorly translated line might imply for a character in a game like X6 which was basically a rush-job in every area, from the level design to the plot and writing, and especially the translation. i think all of us here have for sure put in a hundred times the thought that anyone at capcom ever has.
increasingly mainly cared about Zero past X1.
and if i recall correctly this was always the case, inafune had to be told to design a mega man x, or to make him blue, during the development of the first game, didn't he? because he wanted zero to be favored.