To add further. The queue would look like a problem when first viewed but this would have been set up to keep people off the terminal platform where the southern electric service arrives, allowing passengers to leave the train first. If you dispersed the same amount of people over the up platforms on the main line it would probably be perceived as relatively quiet.
Agree. No one likes to see a queue but it would have moved pretty quick once the Waterloo service was ready for boarding. Better to have it organised than have chaos, which on the small Southern region platforms at Reading could have become dangerous.