I often wonder where this baloney comes from. The notion does seem pretty tightly coupled to the rise of Bitcoin hubbub, which spawned a small army of armchair economists. Inflation primarily benefits the non-rich in two main ways:
1. It inflates away savings, which the rich definitionally have more of than the poor.
2. It inflates away debts, which the poor definitionally have more of than the rich.
Inflation is one of a small set of tools that protects an economy from rampant inequality. Another tool is progressive taxation, which has its own astroturfed opposition in "taxation is theft" and "flat tax" enthusiasts who aggressively call for the removal of things that directly protect them.