The problem with the opposite position, that even the greatest net positive is invalidated if even a single person is inconvenienced[1] (which,
reductio ad absurdum is what you seem to suggest), will obviously lead to practically no change ever. Indeed, it will most likely lead to decline, as any active attempt to change things will probably inconvenience at least a few people, while you can't pin such a charge against passive apathy, even if it long term inconveniences a much greater number of people.
Even the creatives with their coffee shops (generally considered the acceptable level of gentrification, a fact that is obviously totally unrelated to the fact that a substantial subset of people fretting over gentrification are creatives in coffee shops) probably displaces some local activity, perhaps a "brown cafe" loses some customers to the new coffee shop etc.
I recently went on a street-art themed walking tour of Shoreditch in east London, and the guide started the tour by explaining how in the late 80s the area was a total write-off with poverty, violence and prostitution left, right and center, and how entire houses changed hands for as little as £1 -- and ended it by railing against the building of new apartments. The irony of he, himself, being a recent transplant to the area (he alluded to his small-town upbringing, and he was much too young to have moved there pre-1990) did not seem to trouble him much.
Bottom line: clearly there is SOME level of positive development that justifies SOME level of inconveniences. Perhaps we should be a little better at articulating the positive benefits instead of knee-jerk defending those inconvenienced by progress and idealising the gritty urban semi-slums being displaced.
PS: I'm very happy the WaPo link is making you reconsider your position.
1: This article describes the plight of "the poor" being pestered with offer to buy their flats for cash, offers they are perfectly in their right to decline. That's being inconvenienced, not kicked out. http://www.wnyc.org/story/de-blasios-affordable-housing-figh...