Quite correct. Legally, all copies of Amithlon are void unless you own an Amiga yourself (or a copy of Cloanto's AmigaForever) and do not use it at the same time as Amithlon.
Practically, who gives a damn. I mean, really: the product is no longer sold, nor could it ever be sold in the form it was published; noone is able to pay the lawyer bill based on the sales of his product alone in order to ask for advice, let alone settle this matter properly in court. It's nice that we all agree on what's legal and what not, but the market itself has become so small, fragmented and muddied over the years that keeping that stiff upper lip is now much more of a nuisance rather than an asset in keeping the scene alive. Apart from a few brave companies who still back-port their main software (which has long since been moved to the Windows or Mac platform), that's all the Amiga has left, anyway. Even AmigaOS4 is basically stillborn because there is no new hardware being made for the platform. (Unless, of course, it is the new OS of that embedded gizmo ACube put out the other day.)
You can, of course, wait for as long as the law says you must until you are in the clear (70 years after the author's death, with the exception of the US where thanks to Disney you have to wait an additional 25 years), but by that time you really won't be using an Amiga anymore. Not even for hobby purposes.
The situation reminds me to some extent of the scene in Monty Python's The Meaning Of Life where the British army has just been decimated by Zulus, and the officers keep on doing what they always do, namely pretending the real world happens to other people and that there are tigers to be found in Africa.
