Yeah, I imagine they are often projecting their own frustration over parking onto their customers. Every time a customer comes in and grumbles about parking, it triggers their confirmation bias. Conversely, new customers who only popped in because they were on foot are probably less likely to express that fact.

Given how annoying parking is, I'll bet that there are also many business owners who would trade some profit for their own ease of parking. Especially given that they have the power to squeeze their employees rather than bear the full cost themselves.