True, but the T&C doesn't offer any protection with regards to the space you reserved either. FareLock gives you a reserved fare for seven days. ATPCO defines "fare" on their glossary page: it doesn't include a reservation of space.

With this in mind, UA is free to cancel your segments for whatever reason or no reason, as you are not entitled to them. If canceling the segments means that your reserved fare - to which you are entitled - becomes unavailable to you, they should refund the FareLock service charge, similar to how the cancelation of a ticketed reservation by the carrier is cause for a refund.

Arguing the contrary would be arguing that someone who pays a FareLock charge of $10 would somehow enjoy a more protected reservation than someone who purchases a ticket that costs $10k, which wouldn't make sense.