While the incursion was brief, they were warned 10 TIMES in the 5 minutes prior to change course, and it's not the first time they have done it. Russia appears to be doing it on purpose, probably on the assumption that Turkey wouldn't have the guts to respond. Bully tactics really.
It's happened so many times before Russia has previously issued an apology (which they clearly didn't mean). Turkey has a right to defend it's borders, and not doing so may leave them exposed should Russia have decided at some point to target them.
Sure it's going to make things difficult for Turkey for a while - but they had every right to do what they did.