The thing is, most goalkeepers in the league will have a highlight reel like Dave's over a season.
What you will not see in these is how their proactivity, decision making and bravery impacts on the teams performance. Even Dave's biggest fans admit he likes to stay rooted to the line (although he has been sweeping better this season).
Romero and Henderson aren't great, but they weren't shrinking violets and they helped relieve pressure with their actions rather than reacting to the end result of that pressure. This was borne out in every statistical metric measuring team and goalkeeper performance when they played (better save percentages too, but we'll leave that).
De Gea's contract is still in doubt and there are strong rumours we are chasing a keeper, so I doubt people on these boards are the only ones with concerns over his performances.