I don't believe he is taking you for a swindler, just reminding of the requirements of the Home use.
From your further explanation, I would say it doesn't comply with the Home, Non-Commercial use. As per the words 'Public' and 'Clients pay' it matters not what they pay for. There are non-profit organisations, charities, etc. that don't qualify for Home use.
Those people wouldn't be in your home using your home network and if they were guests in your home and using your network I wouldn't expect them to be charged for their connection time.
There was recently a discussion about what is considered commercial use on the forums and this I feel would come under this definition.