I believe this saying initially relates to the prevalence of team work, togetherness, altruism & collective efforts above individuality, selfishness, egoism and soloist effort. In this sense I agree with it.
In such case, “we” is a wellness instead of illness.
I tend to believe in the contrary when “we” (meaning = group thinking or tribal behaviour) results in effects such as “peer pressure”, “group-think”, “suppression of freedoms”, “blind imitation”, “copying bad behaviour”, “suffocation of creativity”, “mobbing & bullying behaviour”, “enhancement of collective ignorance” etc.
In such case, “we” becomes rather an illness instead of wellness.