A better question would be, why wouldn't we announce it? The R already has the information, why withhold it? We announce the foul, the enforcement, unusual situations, timeouts, etc...
By your logic we shouldn't announce anything.
Not exactly. for 50+ years the common practice was NOT TO ANNOUNCE PLAYERS NUMBERS, although as a courtesy, essentially for "coaching assistance" we usually informed the coach of the offending player, for possible remedial action. There didn't seem to be ANY NECESSITY, that anyone else need be advised of the identity of the guilty player.
The salient question might be, What has changed? or Why is it necessary to identify the offending player to the general audience? Is there a purpose, benefit or logical reason for doing so?
Yes, with the advent of televised games at higher levels, and broadcasters quick to share their opinions, the practice has become common, but the same questions apply, which to my knowledge have yet to be answered, even at those levels much less than being necessary (appropriate) at an Interscholastic level.
Logically, the simple question is, WHY, is it necessary to start doing something, that has not been deemed necessary for the past 75+ years, unless of course their is some rational benefit, or need satisfied, by doing so. Hopefully, there's a better justification for doing so than, "because the higher levels are doing so (without anyone understanding, WHY)