Look at it this way, they are saying
uuurrrghh water its bad
yummy our "Chem" is good they don't actually go into much detail of what their system is
ask your customer what they would like you to use( handy hint this is best done whilst drinking from a glass of water)
water or chems
He's just picking up on one failing of HWE and thats. Some of us water boys apparently "might" cause mould or wick back
But then again you could also pick up on one of theres, Some of those "Chemical Boys" might cause allergic reactions, cancer, explosions, have they got to put a warning sign up when they use them? do you have to ventilate the room for a day? don't know myself but hey "THEY MIGHT DO THAT"
Marketing its great ! Personally I think having chem in your name in these environmentally aware days isn't the best marketing tool.