Not bothering to test and actively support devices from other vendors would be reasonable, but customers have the expectation that a product does a decent effort to respect the standard; whitelisting a subset of Philips lightbulbs and deliberately refusing to work with anything else means giving users a bad product for the sake of anticompetitive business practices.
This kind of deliberate, obviously harmful abuse is worse than merely reckless behaviour like the Superfish scandal or the Windows 10 update that uninstalls user software.
Except I don't think Philips advertised that they are using an open standard. It's just what they used for the implementation.
They are free to mutilate that standard as they see fit for their own product, and since they didn't make it into a selling point, there is no reason for them to expect compatibility.
In the world of customers who prefer trustworthy vendors, there's a substantial difference between not wanting to spend money to respect a standard any more than advertised, and deliberately spending money (firmware updates aren't free) to worsen the product and screw customers.
Likewise, "mutilating" a standard to leverage standard technology in a not-really-standard product isn't the same as deliberate artificial incompatibility for purely commercial reasons.
