The anti-high mass proponents will tell you that those designs don't "block vibrations", they just move them to a different frequency (lower) and transmit them longer---in other words, ring longer at a lower frequency for a longer length of time. That's why that crowd in England (all through the 80's and 90's) advanced the notion of very low mass, very stiff supports for turntables, such as Torlyte.
Max Townshend (and Audiogon's own Geoffkait---see above) will tell you that what's needed is a high-pass mechanical filter with as low a resonant frequency as possible. Do yourself a favor and watch the couple of videos on You Tube of Max demonstrating the effects of his Seismic Pod. It's an eye opener!