I am an Intel shill lately but I think it's more of a time thing rather than the desire to keep stuff a secret. They've been pretty good about open documentation on the stuff that matters (like this) such as OpenVINO.
I mean OpenVINO's perf is up there on Intel CPUs and it's a great optimising compiler, I've thrown a lot of weird stuff in there and it didn't crap out with complaints about unsupported layers or unsupported combination of layers. It also has an OK batching story (as opposed to TVM last time I checked...) if you're ready to perform some network surgery.
I also feel it's very bad at reporting errors, and stepping through with gdb is one of the worst experiences... BUT but yeah most of the code is available now.
Now if they could stop moving shit around, and renaming stuff, it'd be great. Hoping they settle on 'OneAPI' for some time.