It reflects nothing but hyperbolic retrospection of the 90th, when Emerging Markets were over levered and the Developed World debts were very low.

Let’s look at the Debt/GDP ratio (vertical axis) vs. the 10Y interest rates (horizontal axis):

It is so striking that Emerging Markets have much lower Debt to GDP (40-80%) vs. the Developed markets of 80-150%, not to mention Japan at 250%!
And Emerging Markets have already higher nominal rates, i.e., they were conditioned (and disciplined) for decades to have high interest rates, and inflation.

So, who do you think is more vulnerable now:
 – South Africa with the 70% Debt and 11% rates,
 – or the US with the 125% Debt and 3% rates? 
while inflation in S. African is lower than in the US?

BTW S. Africa is emblematic of a setup common for EMMs