Unix Domain Socket bind, reuse address

In this context, it's important to understand the rationale for why the kernel has the TIME_WAIT state for TCP connections. This state is intended to allow any packets associated with the connection (that may have taken longer routes or otherwise been delayed) to drain from the network before a new connection on the same port can be established. That way, you ensure that a new connection doesn't receive any packets associated with the old connection. The reuseaddr option enables the developer to communicate "don't perform that wait".

Unix domain sockets don't have that concern; reuseaddr doesn't really make sense in that context.