Because the OP asked why 1986's Aliens was considered problematic now.
Browned-up vasquez is the only logical answer.
Are you sure it's not because it glorifies Xenophobia (to the point even a young child has come to referring to members of another race as "monsters"), and portrays a group of government affiliated soldiers as the "good guys" even whilst they perform systematic genocide on that entire race - ultimately destroying their entire home (including a rather visceral scene where the children of that race are burned alive whilst their mother tries desperately to protect them)?