As long as it's done within the framework and principles of democracy.
No-one in this thread has suggested that any tax-payer can refuse to pay any particular tax.
For the most part Governments spend money on policies which have substantial support and minimal opposition; e.g. education, law enforcement, the NHS. Included in this is expenditure which benefits only a small minority: very few people object to extra help for the disabled. There is also expenditure on minority interests which do not have much public support: e.g. subsidising opera. However there is little strong feeling about subsidies to the arts because most people recognise that the sums involved are small.
The sums spent subsiding railways are not small but most people in this country do not use railways. The question which has been raised is: it is proper to spend such large amounts to subsidise a minority form of transport which is not available to some people?
Yes the government spends a lot on the railways, however if you stopped having the railways you would also loose the tax paid by those railway staff. Which more than offsets the money paid out to the railways.
As such it could be argued that the only tax paid by railway staff pay for the railways and no one else's tax issues for the railways.