They don’t owe you a complete list of reasons why they’re close sourcing their software. They are not a publicly traded company and no one (customers) actually cares if the product is open source or not.
No-one cares if a product is closed-source, a lot of people do care if a product is open source, and really unless a product is truly unique (almost no product is) that is often the main selling point.
Open source software is just a method for corporations to get free evangelization of their product. Companies are now saying “with the assault of AI it is no longer valuable to keep the code open.” They don’t need the handful of Twitter addicted software devs that will evangelize for them anymore because they lose too much by publishing the code. For small companies, the product is most likely the extent of their brand and offerings. Not worth the risk of going out of business, especially when competitors probably aren’t open source.