What about mortgage deductions? Why should a select few (or many) get that while the rest dont?
Because of the scale of it helping so many and for the economic growth/jobs and additional revenue via taxes that come with home ownership. You can't even begin to compare the two in terms of impact and who it helps, not even close. One is a large majority, the other a tiny minority.
Taking that away would completely kill our economy, not so much when allowing a very small minority to deduct their transportation costs.
How about letting me deduct my transportation costs instead? That way it would be fair. Nobody is stopping you from benefiting the interest deduction, but there is plenty preventing me from deducting getting to and from work. It's highly illegal to deduct transportation cost to/from your official place of business and a source of major tax fraud.