这句话是什么结构,However,he said:"Heavy metal or punk fans ended up being much more friendly than the stereotype would have us believe; agreeable,warm.他说：“与传统观念相反,重金属或朋克音乐乐迷有时更友善、热情和平易近人.”---------------------我总觉得很别扭,像有两个句子一样ended up would have

Heavy metal or punk fans ended up being much more friendly，agreeable, warm.---than the stereotype would have us believe
Heavy metal or punk fans ended up being much more friendly than the stereotype would have us believe。这个句子很完整。
在第二个句子的基础上，firendly变化为更加丰富的形容词friendly，agreeable, warm之后，就得到了第一个句子。
再改变一下修饰语位置（为了比较）--than the stereotype would have us believe之后，就得到了你给出的句子。

同意楼上的分析。
个人认为：
end up doing 是一个fixed phrase。
这是谓语。
more than 中的than有时候可以作为代词使用。
其实这样写：
Heavy metal or punk fans ended up being much more friendly，agreeable, warm.---than what（that） the stereotype would have us believe更清楚写。其中warm按理说应该是warmer,可能是并列的缘故。

would have 是用来修饰the stereotype的,意为传统的可以使我们相信,接受,受欢迎等,重金属和朋克等更可以.

是一个句子
从being开始是伴随状语或方式状语从句

是一个句子，前面是分词短语做后置定语，修饰主语Heavy metal or punk fans，句子的真正谓语是would have

would have us believe 都是stereotype的定语~所以语句只有一句啊...

would have之前都是主语

直译起来是这样：
重金属或朋克音乐乐迷有时比传统观念让我们认为的那样更加友善、热情和平易近人。
所以than后面的是从句，more friendly，那么比什么更友善呢，比传统观念让我们认为的那样（the stereotype would have us believe）更友善