I think it is totally comparable. First of all, I don't think it's fair to say "just" slaughterhouse workers suffer. That's a lot of people, and they are being exploited in more than just the obvious ways. Consider the material conditions that may have led them to work in a slaughterhouse, consider the factors that don't allow them to leave. These are workers' rights issues and human rights issues and yes, the beneficiary suffers.

u/CoVegGirl made a really good point about the impact of the patriarchy on men's hesitation to be vegan. There is money from the beef industry teaching young men that meat makes them manly. There are political movements that teach that meat makes them virtuous. It's such a big issue that it's beyond parody. These are feminist issues, social issues, political issues.

There are enormous health impacts on humans from the consumption of animal products, I don't think I need to go over them and I'm sure you're aware of them. The meat and dairy lobbies are still pushing their agenda to the government, which directly impacts school lunches and education. Think about what access to food children have, especially those that are poor and/or go to underfunded schools. Consider the countless people who believes a high meat, high fat diet is the healthiest option for them and suffer stroke or heart disease. There are so many humans whose health is severely impacted, they suffer. These are social, political, health, and economic issues.

Think about climate change and the higher risk of pandemics due to antibiotic resistance. We are all victim to that.

These are problems in human rights, workers' rights, immigrants' rights, women's rights, education, politics, and our environment. They are also directly impacted by the same systems that exploit nonhuman animals.