What were the main technological reasons that Bitcoin Cash did not want to adopt SegWit? What are the key risks/drawbacks to SegWit and why did the Bitcoin Cash community conduct a risky hard fork to avoid it?
There's no technical reason to not to support segwit. 

The main emotional arguments were that this was better done as a hard fork rather than a soft fork, but this ultimately would have resulted in a handful of bytes being different in the resulting block. SegWit was originally designed as a hard fork before the realization that it could be implemented using traditional upgrade paths, to exemplify that. As a hard fork, SegWit would have resulted in substantially more disruption of the network for an almost immeasurable efficiency gain.

Claims at the time that miners could steal outputs from SegWit addresses is demonstrably false. P2SH worked in a similar way, and has the same threat model, even at the time storing billions of USD worth of Bitcoin in its scripts. As the rules are enforced by nodes, rather than miners, this claim is largely based on a misunderstanding of the security model of Bitcoin.