“These soldiers were told, however, that they could have tattoos and that it wouldn’t affect them.”
And they won’t - at their current rank. But at least when I was in, tattoos were very strongly discouraged amongst officers, and anyone getting a lot of them would know it could limit how high one went.
Heck, the first time I was passed over for major, the SQ/CC said it was because my official photo had a wrinkle in the sleeve, and that would indicate sloppiness to a promotion board!
If they hadn’t changed the rules, Mr Rogers, I’d have no problem with it. However, you can’t give someone permission to do something and then punish them for doing it.
Since it requires mutilation to remove these, it is not like approving of beards and then disapproving of beards.
The clear answer is to grandfather those who received tatoos during the time when it was permissible and deny them to all new recruits.