I know that I am repeating what many have stated upstream, but there is an active campaign by some/all of the major airlines against experienced, savvy, etc flyers who are striving to get the absolute maximum value for the purchase currency. Whether that is miles, points, actual currency.

I am assuming the data scraping of airline or other websites as the data source generates unusual loads that allows the site owner to readily identify the source. I believe that several years ago when the ANA award search was the gold standard for Star Alliance award searches, ANA redid their award interface to make it more cumbersome to use and to limit the number if results returned. At the time I believe the public rationale was to reduce the resource load on award searches.

Maybe the solution for the next generation of these tools (and I sincerely hope for a next generation) will be to actually subscribe to the reservations systems/data stores/whatever where the airlines are storing their data. Much in the same way that the OTAs and regular TAs do to do their jobs. Pay the transactional fees for the queries. I think this would have a real impact on the cost of using this kind of service, but it may be necessary to keep this part of the game going.