1/3 of American Millennials joined a boycott in 2018

"In the past year, 33% of millennials and 35% of Gen Xers boycotted a company or product they had previously spent money on, according to a new report from CompareCards.com. Overall, 26% of Americans are actively boycotting a product today.
Men and parents with young kids are most likely to be boycotting a product or retailer, according to the report.
Nearly six in 10 said they're more likely to buy from a retailer or brand that gives to charities or is associated with causes they support. The report compiled survey answers from 1,034 U.S. respondents between Jan. 14 and Jan. 16."

Source:  Research from CompareCards, reported by Retail Dive, 1st February 2019

Note - Compare Cards probably isn't the greatest source, but this stat is pretty eyecatching!