What it means is that the inflation rate remains substantial until 2037 when it will stop inflating.
Even if the inflation flattens out in 2037 and becomes less than 1%, it is always a percentage of total virtual supply, and virtual supply is on an incremental increase, so the absolute number will still be high. In fact, even with a constant inflation rate below 1%, the absolute number will keep rising YoY.
RE: Making sense of Hive's tokenomics: Deflationary in Inflation