It has to keep pinging so the iPhone knows it's still close. Other devices detect that ping; it can't choose who hears it when it calls out.
That's the whole thing: they are constantly calling out to any Apple device in the area so that device will report to Apple the tag's location through the Find My network. It has to call out, otherwise it can't function as a tracker.
Which is where this new standard comes in. Alerting you to an unrecognized device nearby that is pinging out while you're moving, because previously there was no shared standard that permitted this across all devices.
But there's really no good solution to this that isn't going to be messy and trigger a lot of false positives. It's a band-aid on a problematic technology that has been normalized, and now they're trying to back-port privacy into it to save face. All of this discussion should have happened before they started selling anything.
It's bad enough to sell cheap consumer tracking devices and provide access to a whole mesh network of other people's phones to use them on, without any consideration for what they would be used for. It's especially egregious that they made that technology proprietary so Android devices could not easily identify a tracker near them.