Last I heard, the (optional but safe, desirable, and broadly useful) SPV proof opcode was a soft fork. Wanna 'splain your interpretation?
Yes that is correct. The block limit will be raised before Bitcoin is forked (soft or not) to support an SPV opcode.
Secondly, I don't mind at all if a peg operation takes days.
That is a strawman. Nobody said that it would be bad if peg operation takes days. In fact it almost certainly will regardless. The point was that existing users are not going to be rushing to support the addition of blockchain bloating "new tech" while the network is struggling to handle the existing load. The block limit will rise or there will be no support for sidechains.
I've said it before and I'll say it again, I don't mind exceeding the 1 MB limit when it is shown to be desirable as part of an ecosystem which itself has some theoretical hope of being robust and sustainable at scale. A 'one-size-fits-all' Bitcoin as some sort of a one-world currency for every use imaginable is FAR from this theoretical potential. And that's only one of many reasons to reject this absurd pipe-dream.
Not everyone believes Bitcoin will be the one world currency. There are other scenarios however 1MB is so small it presents an obstacle for any meaningful level of adoption. If the average user only makes one atomic transaction between a sidechain and the primary chain every month we are talking about a user base permanently capped in the millions of users. The 1MB limit is artificially low and chosen arbitrarily. Over time it will seem even more ridiculous as bandwidth and storage costs continue to fall. The block limit will be raised or those sidechains won't be using Bitcoin as their parent chain. You can wait for a comprehensive solution to be built out and deployed all at once but it won't happen. The pragmatic approach will be to build out the ecosystem in steps and raising the block limit will be the first one.