That has nothing to do with taxes and everything to do with the lack of a subsidy for those routes.
Taxes and subsidies are not distinct concepts. They are different directions on the same spectrum. In other words "lowering taxes" and "increasing subsidies" are effectively the same thing, merely with different administration methods.
Depending on your perspective, the absence of tax can itself be a subsidy, given that the government may be providing a service without recouping a cost for it.
It wouldn't make sense for the government to give money to a bus company, and then take it back through tax on bus tickets. Rather, before giving money to the bus company, the government should first stop taking money from it. That way the pretty much 100% of the lost revenue from taxes actually goes to the bus company. With a formal 'subsidy', some of that money would be lost in overhead and administration for the subsidy itself, which reduces the benefit-per-taxpayer-dollar.
This is the same reason we don't have any tax on milk at the grocery store. It wouldn't make sense to give money to farmers, but then take it back by jacking up the price of their products.
Small bus companies like Kasper or Hammond are an admirable asset in our rural communities, but they struggle to provide affordable service. Dropping the 13% tax will allow bus companies to survive on less-travelled routes just like an administration-based 'subsidy' would. If pre-tax ticket prices remain unchanged, tickets actually become much cheaper to riders, which will increase ridership, allowing routes to survive which previously wouldn't have had enough passengers. Alternatively, if ticket prices are increased to partially eat up the savings, the break-even point on a given bus trip will occur at a smaller number of passengers, also allowing the company to survive on routes which previously wouldn't have been viable.
