Problem is, you've done something that does not make for civil Civil Discourse: You've staked out personal preferences, cloaked them in fallacious or hypocritically cherry-picked legal cover, and presented them as if your opinions must command universal assent:
"doesn't belong" (a pure opinion)
"exceed recommended height limit" (a fallible, changeable law)
"urban design violation" (a pure opinion on some imagined True Design)
There's a lot to be said for a 200' height limit in the "last block" before the water. Problem here is the garage perfectly conforms to all massing and setback expectations and produces an unassailable economic return exactly as it is. It also abuts two 400' violators, which as much suggests a trend as it does an outrage.
Given that it is perfectly legal and privately owned, There's only two ways that you can presume to get rid of the thing:
Either stump up about $30,000 per resident in boston and buy out the garage (in which case you need to persuade people that that's the best thing to spend it on, not dictate to them), or give the owner an economic incentive to wreck it himself and build a tower.
But its in a city. The answer to ugly buildings in a diverse city can't be take-by-eminent-domain-and-build-a-park...you get Detroit...plenty of new parkland there...
Nope, its going to be "build something" and probably "build something tall."