sassanians were very capable, to be sure and, to be fair, though the article doesn't really specify the date, edessa and valerian were centuries later in rome's history, near the tail-end of the unified empire (30-ish years before diocletian).

so i'm not sure there's a desire to forget about the battle of edessa, or the skinning of valerian - it's in the history, but the tone of the article seems to be regarding the threats to the emerging and established empire and not the crumbling one.