The point you're trying to make is based on the mistaken assumption that they were being unclear. They weren't. Nothing was obscured. No one seriously believed that they meant to imply ownership instead of "you are."
They also weren't doing technical or business writing. It was empathy, which is sometimes helpful.
At the very least, not making an effort to use the correct word is extremely disrespectful of your audience and their time.
When you're in a situation when your message is competing with others, the clearer wording will out-compete muddled wording. That could be in advertising, recruiting, pitching, evangelizing, or any number of places where you want to influence the reader in some way. Every Joule they waste puzzling out your words is one they won't use being influenced (positively) by your message.
How often do you see you're/your confused in professional advertising or press releases? Very rarely.