It doesn’t matter that some ships weren’t nominally owned by Israel but in reality owned by shell corporations in turn owned by Israel-supporting billionaires.
From source Wikipedia, this is not true. Only 3 of 17 have Israeli ownership or ports of call. Do you have a source for Israeli ownership or ports of call for 6 more ships?
Also, your stated class of "owned by Israel-supporting billionaires" is moving the goalposts. That is not the announced Houthi criteria.
The Houthi org certainly has some motivation. Do the facts match the claimed motivation or not?
As far as I can tell Swan Atlantic is owned by a Norwegian company without Israeli ties and had no Israeli ports of call. That means the observed Houthi behavior is still 14/17 (82%) not-Israeli-related.
The Houthi behavior is significantly different from Houthi claims of motivation.