Targeting Amazon just because it's a household brand simply makes an uneven labor playing field - sure, amazon workers might get paid better after your protest, but J J Doe and Sons Glassworkers won't change their ways. Nor will the no-name Ebayers.
However, for me, I realized that
1) I am fortunate enough that saving fractions of my order will not make a material difference to me (the amazon cancellation page informed me that i had saved 140 dollars in shipping using prime over the last year)
2) In the current environment, supporting local and/or smaller businesses is more important to me than saving a day of shipping time, or 10% off my order
3) Even if your alternative retailer is equally unscrupulous to its warehouse employees, for instance, a shipper that uses UPS, which is unionized labor with benefits, as opposed to amazon's own courier service which is contract labor with no benefits, can be a meaningful difference.
For me, the above 3 made me realize that I could do without amazon prime despite being a prime member for 10 plus years. For household staples, I am a costco member, and I feel much better about costco's relationship with their employees than amazons. For other purchases, it makes sense for me to consider local alternatives. And I can always use amazon if I need to, I'll just pay shipping.
Don't let perfect be the enemy of the good. You can push for legislation AND cancel your Amazon Prime. Both are valid strategies for letting your voice be heard.
If an amazon worker gets paid and treated better, then other employers will need to do the same if they want people to choose to work for them.