If you want a copy of the source you can get it via the Open Source tab on most VMware products download page. You'll find the open source distributed for ESXi under the VMware vSphere Open Source group on this page -> https://my.vmware.com/web/vmware/info/slug/datacenter_cloud_...
It doesn't require a snail mail letter as far as I can tell.
Re:VMWare Taken to Court Over GPL Violation
by delinka on Thursday March 05, 2015 @09:38PM
(#9155277)
It's not required to be "friendly" nor is it required to be convenient for you. It's designed to be compliant, internally audit-able, and for free they get the ability to frustrate you into not requesting copies.
I can't imagine a less open-source friendly system...