tl;dr: Balancing tradeoffs and benefits during disclosure is a hard job sometimes and if authors chosen to do it this way - they could have done it for a reason? You don't have to trust me on this, but it has no commercial agenda behind it.
Disclaimer: I happen to work at the same company as authors, not involved in writing this, but I was witness to all research that led to this post. I have seen huge internal arguments on how much and how should be disclosed, given the context (see below), prior to this article being written.
1. I can attest that all these bugs are found in one physical device. I have seen it. Which is really widely used to this day. Moreover, this device has more relatives than we could easily enumerate, some of them potentially vulnerable to a subset of the bugs identified as well. The "vendor" is aware and nothing is changing for a while, in some ways getting worse (blast radius increases over time). This is result of economic reasons, rather than negligence,- "the vendor" in this case is a mixed bag of responsibility between several parties, not all of them commercial, not all of them actually existing to this very date, I believe.
2. In a normal situation, responsible disclosure path, instead of what you've been reading in a post, would be a right way to go. However, context matters in this case: authors happen to live in a country which is at war now (takes like 5 seconds to figure out, looking at the website), so their ability to talk about security vulnerabilities is a bit different to your expectations for reasons that are not very hard to understand. They use vague language, distort a few important details and focus on frivolous illustrations to avoid unnecessary damage.
Pointing out practical exploitability vectors publicly in a way that is understandable to anyone related to the field of practice is sufficiently helpful:
* Some people will now have explanations why their toy cars were stolen and consider changing their supplier of toy car equipment.
* Some people conducting engineering risk analysis will understand that this is not a "potential theoretical vulnerability", looking at their toy car and some of its settings, and consider alternatives.
Consider blog post and examples to be didactic material for an ongoing discussion about some hardware among field practitioners. Authors needed something to point their fingers at and say "this is how X can be exploited to do Y", without reading 2 hours lecture on cryptographic bugs that have been obvious 15 years ago.
3. Why not point out vendor and device list? Consider the context again, please.
It's easy to wave your hand and say "if people are idiots using hardware and devices that are known to be vulnerable, we should let them screw themselves", disclose the name of the vendor, and go on with your life. However:
* Being pointed out directly, these vulnerabilities could easily lead not only to "market levelling out discrepancies" (which does not always happen harmlessly, as we all know). It could lead to more physical damage and deaths immediately happening around authors of this post because exploitation is so easy.
* Not making it would lead to these devices being used over and over again, and obvious cryptographic bugs being dismissed as "theoretical threats", because remote toy car community is full of "Internet of Stuff" people who are dismissing cryptographic vulnerabilities on basis of "it's crypto, who knows how to exploit it, we've got more important stuff to worry about right now".