Bob can't feed himself or his kids on that, so I have to reach into my pocket (taxes) to help him out.
If I didn't do that, Bob and his kids would either slowly starve to death or move somewhere else. Either way, no more employee for you.
Why is it my responsibility to make up the difference, and not the McDonald's across the street that didn't hire him at all? Or the landlord who is charging Bob $400/month instead of $300/month?
What you're saying is perhaps rhetorically appealing, but it doesn't make sense.
You could at least attempt to explain why all the other people who receive the benefits of your generosity towards Bob aren't equally responsible. If Bob starves to death, his landlord loses a tenant. His grocer loses a customer, etc. What makes his employer special?
The others are more subject to market pressures. Take a look all over this thread for some really well-cited explanations of exactly why employment is not like these other things.
There is your subsidy.