First I would citate @TeunVink 's pretty comment. I don't have anything to give it to...
There's a difference between the bluetooth protocol and its
implementations. You get patches on the bluetooth implementation in
Windows 10, that doesn't have to say something anything about how
secure the protocol is. It could be that the patch provides security
fixes for the implementation, but also additional functionality for
specific devices for example.
...except my own findings from a microsoft ex-employee:
Full Disclosure: I worked at M$ from 2014-2015.
MS has some very talented programmers. They're not very common, but they exist. The problem is that the entire company is completely
and totally focused on developing an absurd number of new features and
products, giving them completely unrealistic deadlines, and then
shipping software on those deadlines no matter how half-assed or buggy
The idea is that everything is serviceable over the internet now, so they can just "fix it later", except they never do. This
perpetuates a duct-tape culture that refuses to actually fix problems
and instead rewards teams that find ways to work around them. The
talented programmers are stuck working on code that, at best, has to
deal with multiple badly designed frameworks from other teams, or at
worst work on code that is simply scrapped. New features are
prioritized over all but the most system-critical bugs, and teams are
never given any time to actually focus on improving their code. The
only improvements that can happen must be snuck in while implementing
As far as M$ is concerned, all code is shit, and the only thing that matters is if it works well enough to be shown at a demo and
shipped. Needless to say, I don't work there anymore.
Having many patches doesn't surely mean they are all security patches. They can be much probably mainly compatibility and stability improvements.
Microsoft has a strategy that they try to unify their Windows and Windows Mobile development, which means they try to develop both products from the same source tree. It means, improvements to the bluetooth stack of the Windows Phones can also affect the bluetooth also on the desktop OS - they are probably the same source code.
The main security concern behind the Windows Bluetooth implementation are coming most probably from the Windows Phone - on desktop machines, it isn't even turned on most commonly.
Only these reasons I wouldn't say that bluetooth, as protocol would be inherently bad. It is much more probable, that its Windows implementation has more probably compatibility problems (with earlier software / windows versions) and may have also other problems, partially security-related ones.