The problem with book festivals is that they are trying to turn what is intrinsically an armchair activity into an "event" for popular-populist consumption. Poetry can be read aloud, and, indeed, a great deal of rap and other modern genres are meant to be performance art.
But with traditional poetry, I would personally prefer to lie in bed, slouch in an armchair (legs over the armrest), or sit on a bench in the park, and read the poems silently to myself, rather than have someone else's interpretation thrust upon me. I especially hate it when poets put on funny "poetic" voices when reading to an audience.
Another act of great stupidity perpetrated by the performance-enhancers is having people read in a foyer, corridor, or in the middle of a bustling book fair. People are pushing past, trying to get to stalls, book tables, stands, the lavatory, or the eats & drinks counter. And all the while the poor poet is trying to speak engagingly and with feeling. This is a pseudo-intellectual activity, merely going through the motions of being cultured by having an outer show of such. Unless you can shout down the noise, as Ian McMillan can no doubt do, this is just an exercise in rubbing shoulders with culture.
If you go to a classical music concert you sit on your behind, shut up, and let them play Mahler or Bach; you get pissed in the interval. If you go to a folk concert, you listen, then join in the singsong; you get pissed quietly or singingly. If you go to a rock concert, you can get pissed as noisily as you like, as the music is so deafening that it doesn't matter a bugger whether you yell into the ears of your friends. Once the trendies started trying to "do poetry" in rock concert style, something was lost.
First the bards of yore, then the silent reading of poetry (something learnt over centuries starting with the late Romans, perhaps), and now the push and shove of the drink-spilling classes in the glass-walled, imitation marble-floored foyer. Something has definitely been lost: common sense and a respect for real culture.