This strikes me as slightly unfair. It is certainly true that the emissions reductions by 2030 matter more than the exact year in was which we reach net zero. (There's expected to be a long period before we reach net zero in which net emissions are extremely low, so a few more years of low emissions won't add substantially to our cumulative emissions. On the other hand, even one more year at our current level of emissions will eat pretty noticeably into our carbon budget.) It's also true that Biden's plan doesn't currently specify a 2030 reduction target. However, that's because he wants to use a 2025 reduction target instead, since that would line up with the end of his first term. Biden's climate plan doesn't attach a number to that target, but instead says that it should be set at an appropriate level to ensure we're on track for our climate goals.
Calculating that number isn't easy, since the IPCC doesn't break down the carbon budget by country. Right now, most people (including Inslee, so far as I know) are pretty much just applying the IPCC's global averages to the US. I expect that, if Biden becomes president, his administration will select a 2025 target by just picking a number that looks about right.
In any case, this is all very technical. Biden's plan isn't as aggressive as Inslee's (obviously, since Inslee has the most aggressive plan), but it is still pretty good, and is better than most of the other candidates. Biden initially promised a middle way on climate change, but his actual plan is considerably more ambitious.
Why Jay Inslee picked a fight with Joe Biden on climate change
https://www.vox.com/energy-and-environment/2019/8/2/20751255/2019-democr...