First of all, I'd like to repeat that we are truly sorry that you could not join the tour.
Nevertheless, Viator's policies are clear, and their bad weather cancellation only applies if the tour is cancelled by the operator. So, it does not apply to this situation, as clearly expressed on their support page. There is no loophole.
When you insist on a refund, you're explicitly stating that the cancellation policies you accepted in the booking process were not to be taken serious, and that your personal circumstances are above any agreed arrangement. That does not seem fair.
You did not get the service you paid for because you were not there. That not being your fault, is still your responsibility, a risk that you took when booked.
Finally, leaving bad feedback on our services when there's absolutely no wrong-doing on our side is simply an effort to inflict damage on our reputation at all cost. That could be reason enough for us to get a bit of that "bad taste", but not: we are a small, family-owned company, of 6 people total. We walk the streets under heavy rain or hot sun, in workdays and holidays alike, with the same joy. This company is our sustenance, but mostly our mission. We might be small, but always act in absolute good-faith.
I wish you all the best in your future trips and in life in general.
CEO - Hungry Whales