The DF-21D is a maneuvering anti-ship ballistic missile with a variable yield nuclear warhead. With a nuke, close enough is good enough. That is why the Navy is looking at a defensive laser ABM system.
The Navy could also strike the DF-21D launch sites with nuclear warheads.
Defensive ABM lasers are a great idea: there’s no harm in defense in depth + its good to be able to survive a first strike + ABM lasers allow the interdiction of non-nuclear missiles as well.
But if the enemy threaten the use of tactical nukes then there’s no point in keeping the gloves on.
Without going into details, the DF-21D anti-carrier warhead is non-nuclear, and would be effective at disabling a carrier.