If ask me lots of people don't deserve union protection. Lots of people just suck at working. I'm not here to protect lazy asses.
Unions aren't there to protect individuals. They're there to protect all of the workers. Being against unions because it might benefit a few lazy people is like being against universal healthcare because there might be Trump supporters in hospitals.
Any universal safety net will always also support assholes, but that's no reason against it because those safety nets only work when everyone pays in and everyone gets something out. Being selective about who gets it and who pays for it will break everything, see Obamacare.
No policy will always be perfect because not all humans are perfect. So we should drop this idealism really fast to make progress. Idealism is the source of all extremism.