As others have noted it's illegal to sell pill presses unless you're registered with the DEA, and eBay has gotten slammed for millions of dollars over this.
Their treatment of this seller sucks, but they are also forced to cover their asses by the government on this. So they are in a somewhat difficult position.
I'm not defending eBay, mind you. As the seller notes on their Twitter thread... eBay should and could easily detect this kind of illegal item AHEAD OF TIME when the seller enters the item description. Just block the seller from listing the item, rather than letting them list it... and then banning them later.
It is possible (don't know how likely) that maybe eBay is being total overkill on this stuff as a sign of good faith to the government to avoid future fines. A lot of those fines can be based on the perceived level of willful noncompliance. Not excusing them. Just thinking thru what might be happening.
The regulations concern any manual, semi-automatic, or fully automatic equipment which may be used for the compaction or molding of powdered or granular solids, or semi-solid material, to produce coherent solid tablets.
If the device in question is non-functional, I would dispute the "may be used for" requirement of the definition.
A sword which has been beaten into a plowshare is no longer a sword, and an inoperative 140 year old pill press is no longer a pill press.