Well, outside of the fact that most of the funding is private - lets cut to the chase about WHY we have the inaugurations. This is fund raising. This is where the party cash flow starts happening. The GOP, NRCC and NRSC need the cash flow. I haven't checked this yet but I'm pretty sure that there will be more inaugural parties this year than any other. And you better believe the President is going to be pressing some flesh and making appearances at most of them. This has little to do with real celebrating and has everything to with keeping the machine well greased.
And my tax dollars should be used to pay for fund raising events? I don't think that's even legal.