Because cryptomarket is now a part of the traditional financial market and what is happening with the world economy is directly reflected in cryptomarket. You should not think that cryptomarket is something separate and independent. No, it is not, because big money of institutions (traditional market) was poured into this market.
Only the limit of 21 mln.
BTC makes bitcoin an anti-inflationary asset. How can an asset be anti-inflationary if its price is extremely volatile (it falls and then rises)? Bitcoin could be called anti-inflationary if its price was constantly growing, as in a bullish trend. But as you all know, in a bearish trend, the price of bitcoin falls. Does it mean that during these periods bitcoin is inflationary?

In the long term, bitcoin turns out to be anti-inflationary, to be honest.