I share many of the concerns you've expressed, but worrying about the contract tracing API that was recently put forward is (hopefully) unwarranted. A faithful implementation of the joint spec published by Apple and Google would preserve your anonymity until and unless you published your secret keys. Moreover, the overall design is cryptographically sound (unless I missed something recently?) and appears to be decentralized (at least in principle) so in theory you won't have to trust the behavior of any binary blobs unless you choose to do so.
For more insight into the design (and security) of such systems, you might take a look at the TCN protocol (https://github.com/TCNCoalition/TCN) or the DP-3T protocol (https://github.com/DP-3T/documents).
I don't understand what you mean by tracked here? Until and unless you release your secret keys, the numbers your phone was broadcasting are just random gibberish to anyone other than you.
If you have Bluetooth enabled in the first place, you're already broadcasting a MAC address. Many devices now rotate that specifically to prevent tracking, making it equivalent. In fact the only real differences from your device's MAC are the bit width (tracing numbers are significantly larger) and the fact that tracing numbers are cryptographically derived from an underlying secret.
As far as conditioning massive swaths of the population to be electronically tracked, I'm afraid that ship sailed quite some time ago. Cellphones inherently reveal your (coarse) location in order to operate, modern vehicles carry extensive electronics packages that phone home to the manufacturer, and a seeming majority of people voluntarily upload significant portions of their geotagged lives to various service providers.
I'm about as privacy conscious as you'll find these days, but my only concerns regarding the contract tracing API relate to battery life and the security implications of leaving Bluetooth on all the time (it seems like there's always another zero day being announced).
A minor (but absolutely essential) correction - your diagnosis keys are to be submitted to a database, not your actual location data. Only those who observed one of your previous broadcasts will be able to make the connection.
The notion of a mandatory app or device that tracks location in a centralized manner certainly does make me uneasy. Thankfully that's not (yet?) the reality, but (the same as you) I can easily imagine that an appeal to security might be made in the future to justify such a requirement being enacted.
But the current API, while correlated with that issue, isn't actually related to it in a causal manner. On it's own, the published protocol miraculously manages to yield almost no privacy whatsoever. Even better, none of this actually requires cell network connectivity. You could hypothetically manufacture a Bluetooth-only device (thus no location data leakage via the cell network) whose sole purpose was to facilitate contact tracing!
If we're able to achieve effective contact tracing without giving up our privacy, perhaps it will critically weaken any hypothetical future push for a mandatory app or device that could be used for centralized tracking?
That is exactly what I was thinking of while reading the grandparent comment: that one of the worst things to fear from this crisis, is coming out of it into a world with further consolidation of global power into a handful of entities, and even more authoritarian governments.
The pieces are already being put into place, like contact tracing APIs, however well-intentioned they may be.
The stratification between the rulers (who can already still go anywhere and comfortably wait out a global crisis on private estates or islands) and the ruled, the monitors and the monitored, could end up being worse than any fictional dystopia.