Completely wrong on every level.

The article argues that "I have a boyfriend" means:

The idea that a woman should only be left alone if she is “taken” or “spoken for” (terms that make my brain twitch) completely removes the level of respect that should be expected toward that woman. It completely removes the agency of the woman, her ability to speak for herself and make her own decisions regarding when and where the conversation begins or ends. It is basically a real-life example of feminist theory at work–women (along with women’s choices, desires, etc.) being considered supplemental to or secondary to men, be it the man with whom she is interacting or the man to whom she “belongs” (see the theory of Simone de Beauvoir, the story of Adam and Eve, etc.).

When in fact, "I have a boyfriend" means "I have committed to another." Respecting that does not mean regarding women as property, it means respecting a woman's choice in relationships. Turning that into an instrument of male oppression is, frankly, insane.

Further, "I have a boyfriend" is what we call a white lie. Telling someone you're not interested in that you have a boyfriend when you don't allows that person to save face. Allowing that person to save face skips this conversation:

“I’m not interested.” Don’t apologize and don’t excuse yourself. If they question your response (which is likely), persist — ”No, I said I’m not interested.”

“Oh, so you have a boyfriend?”

“I said, I’m not interested.”

“So you’re a lesbian, then?”

“Actually, I’m not interested.”

“You seem crazy.”

“Nope, just not interested.”

Et cetera. You could even, if you were feeling particularly outspoken, engage in a bit of debate with the man in question.

Here's the subtext of that conversation:

"Hello, I find you attractive and/or interesting."

"I find you unattractive and uninteresting."

"Wait...what?"

"Yep."

"Are you seriously going to stand there and insult me? There's no way you could pad this a little bit?"

"None whatsoever. I refuse to support the male paradigm."

"This isn't about the male paradigm, it's about hurting feelings - "

"How male of you. Allow me to lecture you on how you're not allowed to have feelings because you're male."

Flip it. When a girl comes up to me at a bar and I don't say "I have a girlfriend" is it better for me to say "I'm not interested?" Because from a male perspective, the initial dance is almost entirely "are you hot or not?" So "I'm not interested" is effectively "you're too ugly."

Who is that empowering?