Zombie Pigmen Spawned with Striders Cannot Be Ridden by Other Entities Due to Missing Passenger Tag

Description:
Since the introduction of striders in version 1.16, zombie pigmen spawned accompanying striders have been unable to function as rideable entities for other mobs (e.g., zombies using the /ride command). This issue stems from these specific zombie pigmen lacking the necessary passenger tag definitions, causing them to default to a non-rideable state. All other zombie pigmen spawned through alternative methods (lightning conversion, zombie piglin transformation, natural Nether generation, Nether portal spawning, spawn eggs, or commands) correctly support passenger riding.

How to Reproduce:

1. Locate or spawn a strider with a naturally accompanying zombie pigman rider in the Nether.

2. Attempt to use the /ride command to make another entity (e.g., a zombie) ride this specific zombie pigman.

3. Observe the failure of the riding attempt.

4. Compare with zombie pigmen spawned through other methods, which successfully accept passengers.

Observed Result:

• Zombie pigmen spawned with striders reject all passenger entities and cannot be ridden.

• The /ride command fails with these specific zombie pigmen but works identically with other zombie pigmen.

• This behavior is consistent across all zombie pigmen generated accompanying striders.

Expected Result:

• All zombie pigmen, regardless of spawn method, should have identical passenger capabilities.

• Zombie pigmen accompanying striders should accept other entities as riders when targeted by the /ride command or similar mechanics.

Additional Notes:
This is clearly an oversight in the entity configuration for strider-accompanying zombie pigmen, where the necessary passenger tag was omitted. The bug has persisted since 1.16 and creates an inconsistent gameplay experience. As all other zombie pigman types support riding, this specific subtype should be updated to include the missing passenger tag definitions.