Categorizing what is spam and what is not is pretty subjective, i am sure those who paid 500 sats for a BRC-20 transaction do not think it was spam.

I have not found a way to check the size of those transactions but they are not much different from normal transaction judging by the blocksize in the recent wave, i has not gone up, still in the range of 1.6, those BRC-20 transaction are rather small unlike the normal ordinals that are pretty large in size, but given the FOMO they outbid each other pretty badly.

One more thing worth mentioning is that the pace of finding block has been 6% slower than average, today it picked up to 2% which means more blocks are found per day, this should greatly reduce the fee base.