here is response from SW team:
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Yes, I believe this is related to the app notarization requirement that is enforced starting with macOS Catalina for software distributed outside of the App Store.
In case of apps which cannot be verified, there is a notification like below, and the user needs to specifically allow the application in Security & Privacy Preferences the first time it is executed.


It's a nuisance, indeed, but the good news is that it should now be easy to address. The upcoming IDE 11.3.0 release will be the first one to ship with notarization on macOS, so we have already gone through the necessary infrastructure steps and we are now able to sign/notarize the binaries, so it's just a matter of packaging a signed version of blhost inside the firmware update package.
(As a side note, the readme only mentions macOS 10.13 - so prior to the version that mandates app notarization)
Regarding running as root, now that you've mentioned it, I realize it's inconvenient as it prevents using the utility through double-clicking in UI (and requires using a terminal). I'll need to check if we can do something to relax the requirement.
Either way, we'll update the readme to be more clear.
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pls have a trial.