My guess is that crApple told the customs people that because they refuse to sell the batteries, anything that comes in must be fake, despite it being quite possible that they are genuine second-hand ones.
Well, "we stopped making these years ago and our supply chain ran dry ages ago, so if they are new and have our branding, they must be fake" is a fairly credible argument. I don't think it's terribly likely that there are many used batteries around that are in such good condition that they could pass for new. (Remember, "vintage" is Apple's status for machines that have been discontinued for 5-7 years. So any NOS batteries are likely to be somewhat old, too.)
Apple, like any other trademark holder, must diligently protect its trademarks against counterfeiting, or else they risk losing the trademark if a pattern of non-enforcement stands for long enough. (Disclaimer: IANAL and that's basically a summary of the summaries I found while researching this reply.) IIRC, it's the same reason why Fluke insisted on not allowing those Sparkfun meters into USA, even though Fluke freely admitted they didn't like having to be so hard about it.
So with that said, I think the real question is whether they're actually genuine Apple products or not. If they're fake, then yeah, they should be seized. (I have no issue with third-party parts, they just need to be labeled honestly.) If they are genuine, whether new old stock or used, then I think they should be allowed in regardless of Apple's opinions on the matter.
Where Rossman
really has a point (made in the prior video, his rant while biking) is this: Does an item that was originally genuine, but which has been repaired using third-party components, cease to be a genuine article? Because in that video, he talked about screens being seized that
were original Apple screens, but which had been repaired (cracked front glass replacement) in China. So no, the part isn't 100% original any more, but it mostly is, and the third-party part is not one where the OEM is of much significance. Replacing Apple glass with aftermarket glass doesn't make the remaining parts (such as the flex cable with its Apple logo) any less genuine. Nobody would argue that, say, an iMac whose original hard drive was replaced with a third-party hard drive is any less an Apple product now than before, and I think similar logic should apply to all parts. (In the interest of honesty, I would support rules requiring a disclaimer to the effect of "This item has been repaired using third-party replacement parts.") Yet apparently, those parts have been seized for bearing an Apple logo — a logo which was applied by Apple itself.
One final thought: I do not buy Rossmann's claim of convenient timing. 1) His prior rant about this was before the CBC piece aired, and 2) I don't think that a trademark holder can tell Customs to target a specific entity, not in this way. AFAIK, a trademark holder basically tells Customs to watch for certain types of fakes, and then Customs decides what shipments to inspect. In other words, I wonder to what extent Customs itself is making mistakes in identifying fake items. (And of course, Apple isn't going to go out of its way to prove the authenticity…)