@talwell Any host needs a default route if it is to reach anything not localy resolvable by arp. It is also called the default gateway.
In many linux systems the default gateway is defined as a default (static) route and it IS required in most situations.
The discussion here is about tensor (tnsr). Even though my knowledge on tensor is close to none, it seems that it has its own routing table and is not using the routing table of its centos7 host os. So it is like having two machines in one, and obviously static routing is required for the two systems to route traffic.
I believe this is by design.