You make a very good point, a perspective that I hadn't considered.
However, I do want to point out - inflation generally does lead to higher asset prices, but that does not mean it will go into the equity market. By depositing money in the bank, I think the savers are yielding -0.1%. So if anything, that will discourage Japanese from saving to some extent, or at least discourage them from putting money in the bank. That money could be funneled into consumer prices. In the US, we had high inflation in the 70s with a stock market that virtually went nowhere. I'm not saying that Japan will experience the exact same scenario, and I'm not saying that this particular NIRP policy is what will cause that much distortion in the markets, but months or years down the road, if NIRP becomes the new norm and we see the 10 year yield -3%, and if the markets are saying that they're done with this game, it will be catastrophic. That is a lot of IF's but the first signs are here it appears, and if the market sells off every time they increase the negative interest rates, don't you think it's something to be very concerned about?