I have 2 MFTs, sure they wiggle a little, but I haven't seen how in usage it would matter. I also don't use them as a stand in for a Anvil. I appreciate them having nice solid tops, but overall not too bad of weight.
My comments were simply that people will comment on things flexing, but in a lot of situations it's not an issue and could be a benefit or the less flex option could have much bigger downsides. It's all about the particular locations of a flex.
I suspect MFTs fall into a circular loop, the person who things they flex to much does stuff on them that puts a lot of load on them that makes the flexing seam like a lot more than it would be to others. This extra forcing of it, over time loosens things up more, which causes more flexing and the cycle just snow balls, and eventually you have a table that is completely jello. Since it happened over time, the person never notices the degrading, and just thinks it was like that from the start and or doesn't think they abused it.