It's likely that the average business has a lot more than one owner per business. Most would have multiple shareholders, whether that's husband and wife businesses, or a small firm of several partners. Plus you also need to add in shareholders, etc. Though it's also true that one person can own multiple, and presumably the survey didn't let the same person answer twice, so maybe the 1:1 assumption is ok.
But even so, isn't that figure super low? Here in New Zealand, we have about 550,000 small businesses (less than 20 employees, including self-employed), which if there were one owner per business would make this 10% of businesses.
I'd also add that people who work in small businesses are also more likely to understand what a fine line there is between them having a job and the business going bust. This is especially true for places like hospitality, where margins are thin and businesses go bankrupt at a high rate. These employees may also think it's a bad idea, because they know their business can't afford it even if they are not the owners.
instead are the propagandized proletariat who fight against their own best interest
If you went out on the street and started talking to the average person, I think you'd find that it was difficult to find a person who wasn't voting against their own interests (other than those that do not vote at all).