Nobody is blaming them for someone shooting a missile at them, but from here on I am going to check if I am going to be flying over an active warzone beforehand.
I think there's 0% chance of your ticket being refunded if you don't show up at the gate, and serious chance of finding yourself on a no-fly list if you do show up and refuse to board. Probably near 100% if you are vocal about why.
Keep in mind that most passengers of MH17 were not business travelers. This was at the start of the summer holidays, so many families were travelling together on a holiday. Even if you would have known the flight path, would you have canceled your family holiday (and lose the money) for the perceived risk? Keep in mind that even that day, 159 out of 160 civil flights crossed Ukraine succesfully.
Just to pick a random example: Flight TK7900 IST-SIN is up in the air right now (19:32 GMT on Oct 13, 2015). For a picture of the route, see this.
Over the past few hours, it crossed from Turkmenistan/Iran to Afghanistan a bit north of Herat, crossed the country, passed south of Kabul, then went on to the Pakistani tribal area south of Peshawar, and continued across the hostile Pakistani-Indian border just south of contested Jammu and Kashmir, and then continued over India. There's plenty of conflict in these areas.
Then it was on the Indian Ocean, far away from anyone who could rescue it should something happen to it. Right now it is passing Andaman Islands. If it were forced to land due to multiple engine failure, the passengers perhaps would meet the Sentinelese people.
https://en.wikipedia.org/wiki/Sentinelese_people
And I think Turkish Airlines is perfectly OK to do all this. Should someone shoot down the plane, I know some people would blame the airline. But I would only blame those who shoot it down. It's not okay to shoot down airplanes. Commercial airplanes are not valid targets.
If only reality worked that way. In real war, everything is a potential target - sometimes civilians get hurt by mistake, other times because one side decides to take advantage of the "rules" above and e.g. hide weapons in hospitals.
In general, if an area of land is a warzone and it's known there are anti-aircraft missiles deployed, and there are confirmed shootdowns of aircrafts in the area, you don't fly over that area. Flying there shows lack of practical wisdom. You're betting lives over desperate people following some arbitrary rules and not making any mistake.
In general, exposing yourself willingly to significant danger is stupid, and if anything happens to you, you can't avoid some part of responsibility.
But it was not known there was anti-aircraft missile capability until April 14th (a few days before the MH17 crime). You're making the exact logic fallacy that the DSB criticized in its report.
All incidents from before that Antonov downing on the 14th were done using MANPADS (i.e. shoulder-carried missile launchers). These don't reach high altitude. The information about the new capability wasn't relayed quickly enough to commercial aviation authorities (I don't think the DSB identified a reason for the delay).
Instead, the DSB argued that risk assessment for fly/no-fly decisions should not only include known risks, but should also account for unknown risks (say, the speculation that the rebels did have anti-aircraft capability).
(edit: although another source says that the rebels' STA capability was known since June 29th)
The report is quite clear : the Ukrainian authorities were aware of the threat, and had good reason to close the airspace BEFORE this happened. This is in fact one of the few pieces of blame being laid out here.
That means the only real remaining question is whether the Ukrainian authorities were using commercial flights, and the lives of thousands of passengers as human shields to safeguard their military aviation in the area, were they trying to provoke Russia into shooting down commercial planes or was it merely a monumental fuckup ?
It seems we'll keep seeing every attempt being made to shift the blame on Ukraine, not the ones who actually decided to pull the trigger. Russia is active in stopping an investigation to find out who it was. That tells me a lot.
Passenger planes routinely fly over conflict zones. A plane flying at >10 km cannot be mistaken for a fighter-bomber. Unless the operators of BUK were, well, drunk, which is still what I suspect, but equally irresponsible.