Here's a third option: the five month old anonymous HN account claiming to know what the H2 designers were thinking of is wrong. How would you compare the likelihood of that to your two options?
The main problem you're talking of is head of line blocking due to packet loss. But packet loss as a congestion signal is nowhere near as common as people think, and that was already the case during the original SPDY design window. End-user networks had mostly been set up to buffer rather than drop. (I know this for an absolute fact, because I spent that same time window building and deploying TCP optimization middleboxes to mobile networks. And we had to pivot hard on the technical direction due to how rare packet loss turned out to be on the typical mobile network). The real problem with networks of the time was high and variable latency, which was a major problem for H1 (due to no pipelining) even with the typical use of six concurrent connections to the same site.
Second, what you're missing is that even a marginal improvement would have been worth massive amounts of money to the company doing the protocol design and implementation. (Google knows exactly how much revenue every millisecond of extra search latency costs). So your "marginally better" cut isn't anywhere near as incisive as you think. It also cuts the other way: if SPDY really had been making those metrics worse like one would expect from your initial claims about H2 performing worse than H1, it would not have launched. It would not have mattered one bit whether the team designing the protocol wanted it deployed for selfish reasons, they would not have gotten launch approval for something costing tens or hundreds of millions in lost revenue due to worse service.
Third, you're only concerned with the downside of H2. In particular HPACK compression of requests was a really big deal given the asymmetrically slow uplink connections of the time, and fundamentally depends on multiplexing all the requests over the same connection. So then it's a tradeoff: when deciding whether to multiplex all the traffic over a single connection, is the higher level of vulnerability to packet loss (in terms of head of line blocking, impact on the TCP congestion window) worth the benefits (HPACK, only needing to do one TLS handshake)?