03考研英语text2这句话anyone和would的用法是什么意思？anyone不是用于否定和疑问么？

Hearing allegations of cruelty to animals in research settings，many are perplexed that anyone would deliberately harm an animal.

另外，如果这里的anyone可以用于肯定陈述句，那么03真题的完型(A variety of activities should be organized 35 participants can remain
active as long as they want and then go on to 36 else without feeling
guilty and without letting the other participants 37 .）这里的第36题必须填something而不能选anything