Library destruction was routine. It could've been burned, partly or entirely, on more than one occasion.

Neglect is also possible. What happened will likely never be known because there's no existing evidence.

So we're potentially psychoanalyzing a non-person over a ~1700 year gap..

When there is conquest or rebellion there is death and destruction. I don’t think there is likely more to it than that.

If it was premeditated then is it the equivalent of modern ‘book burning’ and a cultural cleansing. History is strew with cultures being wiped of the face of the Earth with little remaining other than a few shards of pottery. Thankfully we have actual written accounts from the period that have survived and to my knowledge there isn’t anything substantial to suggest that it was done for any particular ‘point’. Much like Christians loping off cocks from ancient statues.

the most deadliest kind of barbarism usual comes under the guise of ‘civil society’. Such is the stupidity of humans - it’s not all death and destruction though! :)