First of all, I think home distillation should be legal as long as it's for private use. But, I thought of a good rationale for homebrewing / winemaking / etc. to be legal while distillation remains illegal. Homebrewing and winemaking can happen by accident. Indeed, it very likely will happen by accident in any case where a sugary liquid is exposed to the air, or to fruit, or grain, or any number of other sources of wild yeast and bacteria. Spontaneous fermentation happens. Is it reasonable to ask your citizens to discard the results of a natural process that takes place in their home, simply because the result includes alcohol? Most reasonable people (and all True Scotsmen) would say no. A similar rationale can be applied to freeze concentration, which is also generally viewed as legal. But, distillation is not a natural process. It is an intentional man-made process which implies an intent to manufacture an alcoholic beverage. So, that's where they're drawing the line. Is it reasonable? I say no, but I can see how some True Scotsmen might say yes. Similar to how the line is drawn between allowing poppies to grow in your yard, and harvesting opium from those poppies (no comment on whether or not I think that ought to be legal).