Maybe wait with the judgements until the report is in? There are so many possible reasons why this could have happened that have nothing to do with the two items you listed (though it maybe that it does, it is just a bit pointless to assign blame before you know what the cause of the accident was).
You may well be right. Or... maybe there was a non-stress related manufacturing issue with a turbine blade. Maybe it ingested a bird, maybe it sucked in some crap lying on the runway. Maybe there as an issue with a part that was replaced during the 2 hour service just prior to the flight. Maybe there was an error during that service, or a defect that was overlooked. And a million other possibilities.
There has been at least one crash due to manufacturing defects that no one knew about beforehand or could therefore diagnose. We will find out what happened in about a year once the investigation is complete.
Phase of flight is a major contributor to accident statistics with take-off and landing much more often associated with accidents than the rest of the flight.
Take-off asks a lot from the engines, and one nasty bit about manufacturing defects is that they can take a while to show up, but the bulk of them usually surfaces when the aircraft are relatively new.
But: this plane was delayed before the flight due to maintenance on engine #1, so that's the first place where I would start looking for issues without any kind of judgment beforehand on what you would expect to find. And that's the main issue with that comment, it assumes a conclusion, that's not how these investigations work because then you might miss the actual cause. And given how critical these machines are it doesn't take much. All it takes is a single, tiny mistake.
The really bad luck here is that it seems as though the failure of engine #1 took the center engine right along with it. That's one of the issues with that particular design, if you have debris from one of the forward engines it could easily get ingested by the rear mounted one.
Trust is hard to earn and easy to lose. It'll take a while before we look at American planes through lenses other than Boeing straight-up lying.
I mean the engine is laying on the side of the runway and the plane is seen on fire trying to take off; I'm going to go out on a limb and say maintenance was somehow involved.
Well-maintained planes don't do that.