The chart is more than a little misleading and the operating range is not special
In the context of this article, without any other labelling the presentation of the ASHRAE guidelines is rather poor. The ASHRAE "guidelines" shown on the chart are the "recommended" range, that is the range you should set your default operating conditions to. Pretty much any server purchased now will conform to at least class A2 which requires operating up to 95F and 80% Relative Humidity, instead of the measly 80F and 60% max Relative Humidity, the "A" range in green on the chart (which is just not relevant).
Class A2 is the standard for any vaguely decent server, the only issue the climate plotted on the chart shows is the upper dew point which is substantially above the 69.8F of Class A2. (IBM rate their mainframes to Class A2, I would not call this adventurous or pushing the envelope).
Any decent cloudy operator however should be buying tin to match their operating environment and not the other way around. Class A3 and A4 equipment is available, Dell even do mainstream retail servers that reach Class A4. Class A3 servers are rated to 104F intake temp, 85% Relative Humidity and 75F dew point which fully covers the operating range shown on that chart without even going custom, and the whole point of ODCA and OCP is supposed to be custom designed tin to meet the spec isn't it?
For those who prefer their units civilised;
legacy "recommended" - 27C, 60% RH 17C Dew Point
Normal Class A2 - 35C, 80% RH, 21C Dew Point
Class A3 - 40C, 85% RH, 24C Dew Point.
Oh, and no, whatever FUD your IT vendor spreads, the world won't end if you let your server intake go over 25C.