“Feeding” a rental property vs retirement account

[Ben Nelson]

Why are people generally not ok with “feeding” a rental property with negative cash flow, when they basically do this every day with standard retirement accounts? What’s the difference between putting extra cash into a hard asset like real estate vs taking cash out of your pocket to invest in stocks, etc.?

I’m not necessarily saying I’m a proponent of buying cash flow negative property or using this logic to justify it, it’s just curious to me why it’s so readily accepted to take money out of a paycheck for say a 401k, but not so much to put that money into a negative cash flow piece of property. Would love people’s thoughts on the mindset here. :)