according to the press release from the FIOD, operational servers were dismantled and seized in the netherlands and luxembourg. very sloppy of bestmixer to be running servers out of such jurisdictions.
I agree that it was not wise to use servers in those two countries, and the same would happen anywhere in the EU probably. Mixers are not popular in the eyes of the authorities, because they are considered as services that enable money laundering, which is not exactly true. The fact that they can not control them leads to actions like this one.
I do not know where the servers of ChipMixer are located, but I hope they are not in EU / US - in case this is just the beginning of the attack on similar services.