The Nestle boycott wasn’t founded due to exploitation of employees, unions, etc. They’re shitty and do all that stuff (and far more). But the boycott was specifically founded (in the 1970s) due to their decision to relentlessly market baby formula to vulnerable mothers, particularly in less developed countries, often in times of famine or hardship. They knowingly caused health problems in infants (who of course then grew into adults with health problems), probably caused many infant deaths, and pushed families into poverty (with all the consequences of that), for profit. 50 years later we’re still dealing with the consequences of their immoral marketing (which has never really stopped, they just change the messaging in order to comply with relevant laws, which are too weak).
I’d boycott them just for that, but they’re also the corporation who in both U.S. and European hearings has argued that water isn’t a human right and pushed to privatise community resources, at a time when water scarcity is one of the main long-term threats to many countries, including the U.S. and many European countries.
Other companies do this stuff too, but generally speaking they’ve done it for less time and are less brazen about it.
Nestle (as of last year’s financial returns) owns 20% of L’Oreal (L’Oreal details on last share sale, Nestle statement of its relationship with L’Oreal). They reduced their holdings a couple of years ago (down from 23%) but at 20% they’re still one of the more significant L’Oreal shareholders (though not the largest at L’Oreal).