Scientists may have the right to investigate anything within their means, but that does not mean that they also have the right to the means to investigate anything they choose.
1.  to the means 不多余。这个句子有点意思，连用了三个means，有点绕口令的味道。可能是，作者为了比较三个means 的不同含义。

within their means：力所能及

the means：那些手段

that does not mean：那并不意味着

2.  have the right to the means：right （权力）后面可以接不定式，也可以接介词 to，词组的意思是 “拥有使用这些手段的权力”。to investigate anything they choose 作the means 的定语。这个词组强调说明 “有权采用这些调查的手段”。
【翻译】科学家可能有权调查他们力所能及的任何事情，但这并不意味着，他们也有（调查他们选择的任何事情）所采用手段的权力。