It's obviously quite hard to hit a fast moving object.
But even with /tick freeze you just cannot interact with the minecart at all.
Hitting it doesn't destroy it nor damage its passengers.

Reproduction Steps

• Build a loop for a minecart to speed up in
• Set minecartMaxSpeed to 1000
• Do tick freeze
• Try to hit the minecart

Observed Result

• You cannot destroy the minecart
  tick freeze(1).mp4

Expected Result

• You would be able to destroy the minecart