Trump complained in tweets that he wasn't getting enough credit for his
meeting with Kim and railed that "Much of our news media is indeed the enemy
of the people" as he headed to sit down with Putin.
这里的as是关系代名词,
Much of our news media is indeed the enemy
of the people的先行词
还是做为 "因为"解释
如果是关代
那这句的意思怎么说比较顺呢

应该做“当……的时候”解吧！“在启程前往俄罗斯与蒲亭会面的同时，川普透过推文抱怨道……”

THX

也可能我见解错误，望请指教。