Of course not, they don’t have to. Most NE players draw a clear distinct line between NightElves and Highborne, simply because the NightElves eventually turned on Azshara once she went too far off the deepend. But they lived in relative comfort within her Empire prior to that for thousands of years. Blizz deliberately leaves that opening for cherry picking with Alliance races. They do the exact same thing for the Draenei, even though their species the Eredar has shown an unbelievable tendency towards world ending crusades twice now.
As for the Horde in BfA. Honestly, I don’t mind the WoT itself. Saurfang’s plan was one that depended on the survival of the NE civilization and leadership to put pressure on Anduin; its was not a plan to eradicate the NEs. The Alliance had also been acting aggressively up to that point, with several acts that should have been considered “Acts of War”, but weren’t simply because Blizz ensured they were weakly invalidated or excused. Solely so the Horde could be the aggressor (the same thing that happened in the Garrosh War tbh).
Sylvanas was also absolutely right in her arguments to Saurfang that Tyrande and Genn were tryiing to pressure Anduin into pre-emptively attacking the Horde. The only thing she was really wrong on was Anduin buckling under that pressure. But considering she used Anduin’s response to Genn and Roger’s actions in Stormheim as evidence that he would (or worse, that he was complicit in or supportive of that attack) … it is very understandable why Saurfang believed that Anduin would concede to his elder’s wishes and attack the Horde first.
Also, as much as NE fans LOVE to ring the “Genocide” Card. Technically, unless you’re conflating Saurfang’s WoT and Sylvie’s decision to burn the tree, the Horde was made a “Tool” for Genocide. There was never the intent for anyone outside of Sylvanas and her most diehard loyalists to eradicate the NEs. Its still horrific, but this is not quite the same situation as the deliberate attempted genocide as say the NEs partook in under Cenarius against the Orcs in WC3; where they fully intended to purge them all because he falsely believed they were agents of the Legion.