Clearly up to no good but unknown if the “no good” involved bringing down the the plane. a lot of other criminal activities could be involved
You’ve nailed it, everyone is looking at the stolen passports thing and immediately jumping to the conclusion they must have been terrorists without thinking it through.
Why would terrorists on a suicide mission worry about being identified? Why would they book onward flights?
The passports were stolen in Thailand, the tickets were bought in Thailand, the onward flights were to Amsterdam.
Drug smuggling anyone?