Thargoid Interceptors will aggro (attack) onto whichever player has the highest Threat. Threat is calculated based on highest damage dealt to the interceptor since the last time it changed target. Whenever a Thargoid changes target, it will be unable to change target for ~35 seconds (Target Swap Lockout) or until the target dies or leaves the fight. During the target swap lockout, any damage dealt to the Interceptor will be considered for the next target swap, however the Interceptor will not actually change target until the lockout period has expired (or the current target has died/left).
Threat can be increased by dealing damage. This can be beneficial for various reasons.
Controlling the Thargoid's Movements.
Saving another CMDR from death.
Giving another CMDR an opportunity to ram a Thargoid.
A good example of this is the following:
CMDR1 is kiting the Thargoid around with full aggro.
CMDR2 uses his weapons to take the aggro and distract the Interceptor.
CMDR1 uses the Target Swap Lockout window to ram the Interceptor without any threat of being hit by Lightning.
A wing fight with lots of Threat Management Tactics