That was because the USS Monitor was one of the FIRST Ironclads, not because it was one of the best. At the time the comment was made, the "no European vessel" comment is in-reference to wooden ships, because European navies didn't really have Ironclads at the time of the Monitor besides the La Gloire and Warrior.
I also love the "aside from the HMS Warrior" comment... duh... the HMS Warrior was an ocean-going ironclad cruiser... and I'd bet the iron-plated ship-of-the-line La Gloire would at least fight the Monitor to a draw, if not defeat it... unless they left coastal waters, at which point the Monitor would sink in heavy seas (like it did historically).
Sorry... but there is absolutely nothing special about American Ironclads of the Civil War, other then the fact they were the first ironclads used in combat... in fact, most were quite inferior to European ironclads, simply because Americans (for the most part) concentrated and river gunboats that were unworthy for ocean-travel, while Europeans (when they got around to making ironclads) were producing ocean-going frigates and ships-of-the-line in ironclad plate.
The best thing the USS Monitor had going for it was its turret design... but even that was not enough to defeat a more traditional broadside-armed CSS Virginia.
In the matter of ironclad hierarchy, designs like the CSS Virginia and USS Monitor are definitely on the bottom-end of the Ironclad totem pole. Consider the USS Monitor and CSS Virginia as roughly equal designs (since they battled to a draw), then consider that the CSS Tennessee was a larger and better ironclad gunboat then the CSS Virginia... the CSS Tennessee was defeated by Northern Ironclad Steam Frigates in the Battle of Mobile Bay, since the very design of the gunboat was too small and too slow to keep-up with ocean going steam ironclads such as the Union eventually employed, and the Europeans mastered.
Sorry Thinker, but there's nothing very special about the USS Monitor or CSS Virginia design that makes them superior to other ironclads, especially ocean-going ones, of which both would be too slow to gain any advantage on (see the destruction of the CSS Tennessee as a reference). The comment you cling-to refers to the English reporter referring to wooden warships, which were indeed made obsolete by all Ironclads... the USS Monitor was an early Ironclad, and the first to engage in ironclad to ironclad combat... but it was neither the first ironclad built, nor even the best ironclad when it was launched (the HMS Warrior already existed and was vastly superior in every measure).