Looking for help understanding a passage


I'm looking for some help understanding the passage below. I've highlighted in
bold the parts that have me a bit stumped.

> 楽しくあれ。葵さんに言われ続けた言葉だ。
>
> 一度は背を向けて、見ないふりをしていた言葉だった。
>
> なのに結局、俺はこの言葉へと戻ってきた。
>
> すべてはそこに集約されるよう、最初から決まっていたかのように。
>
> 確かに、楽しいというのは強い言葉だ。
>
> これが使えればどこへだって行けるし、誰とでも打ち解け合える。
>
> **でも使う人間がどん底にいる時には、この言葉は自らを傷つける凶器にもなる。**
>
> **そこに至るまでの道を示して、丁寧にしっかりと手を引かなければいけない。**
>
> **誰彼構わず使える言葉ではないのだ。**

I'm sure I am misunderstanding something which makes how this should be
understood obvious, so I would appreciate it.

The first line:

でも使う人間がどん底にいる時には、この言葉は自らを傷つける凶器にもなる - I think this sentence must mean
something along the lines of "but if the person who uses this word is at rock
bottom, then this word can become a weapon which hurts oneself".

The second line:

そこに至るまでの道を示して、丁寧にしっかりと手を引かなければいけない。 - This seems to be referring to the person
at "rock bottom", and that they need to be firmly, but gently, shown the way
there (i.e. out of どん底 and towards 楽しい).

Third line:

誰彼構わず使える言葉ではないのだ - Here I was not entirely sure how to interpret 誰彼構わず. Doing
some googling for example sentences e.g.:

相手はキリスト教徒じゃないかもしれないから誰彼構わずメリークリスマスというのはやめておこう - Be careful who you speak to.

強力な力ってのは、それを使えるだけの知識と技術と倫理観を持っている人間だけが使うべきであって、誰彼構わず使えるようにすべきものじゃあないのだ - Not
everyone can / should be able to do something.

This to me suggests that 誰彼構わず使える言葉ではないのだ could be interpreted as either This
word (楽しい):

  1. cannot be said to anyone (without thinking about who they are)
  2. cannot be said by just anyone

If my interpretation of the first two sentences are correct, then this would
be #2 (cannot be said by just anyone).

Have I understood this correctly, or am I misinterpreting/understanding this?




  * This 使う人間 is an example of [ambiguous-relative-clauses](/questions/tagged/ambiguous-relative-clauses "show questions tagged 'ambiguous-relative-clauses'"). It can mean both "someone who says 楽しくあれ" and "someone who I say 楽しくあれ **to** " depending on the context. So who is "at rock bottom" in this context, and who is saying 楽しくあれ? Is this person (俺) trying to encourage someone else who is at rock bottom but worrying about hurting him/her? Or is he at rock bottom himself and recalling the word said to him? If the context is the former, the sentence would roughly mean "Saying 'Have fun' to someone who is at rock bottom may hurt him."
  * Your understanding of the second bold sentence is correct.
  * 誰彼構わず is a fixed set phrase meaning "regardless of who (the target is)", or simply "indiscriminately". The sentence means "It's not a word one can say to anyone."

