The reason why there was only VC in a Steam version of Toribash is because Steam have their own solution for it, which as you might expect depends on Steam API and thus won't be available neither on standalone builds nor on mobile. There are just no easily available VC solutions that work everywhere - that's a common issue with even some major games where VC would only be locked to current platform.
I understand where you're coming from (especially with matter of convenience) but yeah, considering it was such an underused feature in past that also came with a bunch of its own problems that it's unlikely to see a comeback.
There's Discord and plenty of other third-party software that allows you to VC with your friends, that's probably your best bet. With Discord specifically, you can use the public VC channels in Toribash server if other people in the room are willing to talk. Standalone software also typically offers wildly better VC quality and performance compared to Steam stuff we've used as well, it's kinda their main focus rather than just a side feature.