I can't seem to read the twitter comments but I don't really see that here, at least in top level comments it seems to be all people who are quick to jump from that to making excuses or trying to rationalize why these numbers are "bad".
I don't know what would be the problem with talking about economic stagnation though, significant differences in GDP growth between ~comparably advanced economies doesn't seem like a bad starting point for that, does it? I notice you didn't actually reply to such a comment, but even so I don't know why you would bring life expectancy into GDP stagnation either. There's certainly a fairly strong correlation and almost certainly causal relationship, but nobody seems to be confusing GDP with the sole driver of life expectancy or believe that GDP tells "the whole story". So it seems like a weird thing to bring up, you could also bring up wheat production and point out that it isn't fixed to GDP, because it also doesn't tell you that story.