My point isn't really "no speculation is allowed", but that we should be honest about the assumptions we're making. The Guardian headline that kicked off this thread uses misleading wording to hide the assumption being made. It's fine to criticize ICE based on informed speculation if we're honest about it.
And my point, again, is that focusing on this particular criticism[1] seems like a transparent attempt on your part to deflect from the very serious story (ICE transparently harrassing "enemy" journalists without apparent cause) because, hey, maybe he failed to declare an agricultural product in his luggage. We don't know, amiright?!
It just doesn't seem to be a good faith discussion of the situation, and in particular it makes your position seem decidedly pro-secret-police.
[1] Which amounts, basically, to "Mildly sensationalist mid-tier news outfit used a sensational headline". It's boring.