I'll take the excuses , it may be because some people aren't using C2 properly because they don't have much of experience in game development in general ... but that's ok , because C2 is designed to be high level , but don't expect to throw at it two nested loops and figure out why it is slow , moreso , C2 was designed as a game engine and should be able to be able to handle all 2D games , thus going overkill with even the simplest games , like polygonal collisions where a game only need tile-based collisions , thus you can't compare code that was written for a sole purpose and game engines , where that code was only created to run in a way , but C2 created to handle in an all-in-one fashion , and that MAY be the reason why it can be slow for simple games in some people's opinion
That answers the two quotes above , and remember , you can't compare code to a game engine , it's like comparing a ... uhm ... eh ... ( bad example incoming !) a swiss knife to a kitchen knife , The two of 'em are the same weight , but the latter cuts meat better because it was specially designed to do this task , as of , the swiss knife can do WAY more than just cut meat , and therefore is superior for bigger tasks and such , but that's probably not a good example
<img src="http://www.thestyleking.com/wp-content/uploads/2012/12/victorinox-swisschamp-xlt-swiss-army-knife.jpg" border="0" />
<img src="http://www.photo-dictionary.com/photofiles/list/7261/9718kitchen_knife.jpg" border="0" />