Think of the statement as “backwards time travel existing would break our model of causality which has so far held up to observation.”
It’s essentially Occam’s razor. Of course we could currently be wrong, but the entire point of the western scientific mindset in which this article is written is that we can be reasonably certain that in this case we’re not. If you want to dedicate your efforts to showing otherwise, have at it. No one will stop you. They probably won’t fund you though, and on the minuscule chance you end up being right unless it’s blindingly obvious it’ll take a while to convince people (we still haven’t convinced everyone that the standard model matches experimental data as well as it does, and that’s more or less been settled for how many decades now?)
It’s essentially Occam’s razor. Of course we could currently be wrong, but the entire point of the western scientific mindset in which this article is written is that we can be reasonably certain that in this case we’re not. If you want to dedicate your efforts to showing otherwise, have at it. No one will stop you. They probably won’t fund you though, and on the minuscule chance you end up being right unless it’s blindingly obvious it’ll take a while to convince people (we still haven’t convinced everyone that the standard model matches experimental data as well as it does, and that’s more or less been settled for how many decades now?)