It took the US until like 2006 to get soldiers to stop filming themselves throwing puppies off cliffs (actual event), and even since there’s been a number of incidents, and they’re significantly more centralized than Russia’s military. This isn’t “pass along a message”, militaries are a huge organizations, with disparate practices and politics. Just because there wasn’t a high-level order increasing the penalty for having a phone on the front line doesn’t mean that it wasn’t restricted before, just because there is now doesn’t mean it’s going to be followed 100% of the time.