I see no reason to get upset over this - 1 make / model racing has always been around, especially in Road Racing.
In fact, take heart in it - when one model series are launched well after the bikes introduction, you know it's last gasp stuff.
If they would have done this from the word go - they may well have had much more success with the 150.
Better still, they could have stuck within the rules and made a 125 ( which was allowed against 85cc 2ts )........... well, no, Honda realized that would be a disaster, so they just tried their usual tactics. The rest of the world bent over for them , for once the AMA stood up to them. Wonders will never cease.