That is definitely not the case. There are plenty of employers making things worse. One of my first jobs was for a telephone fundraising outfit. We'd cold-call people, manipulate and like to them, so they'd donate money for our charity of the week, and keep 85% of it.
Making society better requires actually making society better. You have to weigh the total societal positives against the total societal negatives.
OK let me qualify my answer. Voluntary financial arrangements are beneficial to society that do not harm others. The government in capitalistic systems enforces the rule that you can't harm one another arbitrarily. So an assassination contract would be illegal. Also, defrauding people with cold calls of their money is illegal. In short, LEGAL voluntary arrangements in a free market are beneficial.
That's progress, but you haven't accounted for negative externalities or the varying shades of "voluntary" that exist. Both of which occur in pretty much any job people take these days.
Making society better requires actually making society better. You have to weigh the total societal positives against the total societal negatives.