IMO, Biden is announcing that the justice system, at least at the federal level, is either broken, easily abused (politicized), or both. He obviously feels the people whose sentences he commuted were not tried or sentenced justly, and he's therefore stepping in to balance the law against just and fair treatment.
That, or Hunter gave him a list of drug dealers, suppliers and users he wanted to start partying with again.
The vast number of his orders are commutations. As for the preemptive pardons with no charges or verdicts to name for family and administration cohorts, the motivation is too obvious.
Pardons have a legitimate purpose. What Biden is doing exceeds those bounds by a lot. He's intentionally putting up walls around his chosen few to shield them from the consequences of their crimes. That's not the purpose of his Constitutional power of the pardon.