I don't think and anyone is saying that using the bot is illegal. The issue is that DoNotPay is calling the bot a lawyer and therefor implying that it gives legal advice. Their website literally says "World's First Robot Lawyer." Someone who doesn't understand AI might wrongly think that their AI tools are qualified to represent them on their own.

I suspect that it would be much less of an issue if it was advertised as an "AI paralegal."