No, that's inflation slowing down. But its still inflation, because new coins are being created.

You are correct the parent is not referring to deflation - just slowing inflation. However Bitcoin is strongly strongly deflationary because any random walk down the timeline leads to 100% of coins lost. Due to human error, act of God and chance. In its first 12 years, give or take 20% of all Bitcoins were lost in spite of, what, 80% of all coins being generated. Thats an annualized deflation rate of 2%.

The real value of one Bitcoin today (I.e., the dollars or goods one could exchange it for) is absurdly higher than before, so it deflationary as the term is usually used.