You do realize that the people that signed that 'agreement' only represent themselves and nothing more?
Yes
what I see happening, assuming that Core does agree to do a 2 MB block size limit for this reason that you've mentioned, is :"We've succeeded in pushing 2 MB blocks, it is time to go further. 4 MB blocks!"
That is why we need to mitigate this risk by taking the action only when Classic looks almost totally defeated, with a 12 month grace period, a 95% activation threshold, in two steps (softfork flagging the hardfork, then the hardfork itself) and only to 2MB or smaller. There is another risk, which is that we avoid doing a hardfork only to avoid the perception that these aggressive inappropriate attack tactics work.
Do you really think that with all that was said in /r/btc that most (not all!) of these people have any kind of respect for the current (Core) developers?
The level of stupidity in /r/btc is so severe that I even suspect some small blockist agent provocateurs may be contributing to it.