hinanzyo de ha, siranai hito ni mo sinsetu ni hanasikakerukoto ga taisetu da to omoimasu.

では is で + は.

• で marks the place where an action happens.
• は makes that place the topic or setting of the sentence.

So 避難所では means something like in evacuation shelters, as for that situation... or at evacuation shelters.... It sets the context before the speaker gives their opinion.

Literally, 知らない人 means a person I do not know.

In Japanese, a verb in plain form can directly modify a noun. So:

• 知らない = do not know / don't know
• 人 = person

Together, 知らない人 means a person you do not know, which is a natural way to say stranger.

This is a very common pattern in Japanese:

• 日本に住んでいる人 = a person who lives in Japan
• 昨日会った人 = the person I met yesterday

The verb 話しかける means to speak to someone, to start talking to someone, or to approach someone verbally.

The person you speak to is marked with に. So:

• 人に話しかける = speak to a person
• 知らない人に話しかける = speak to a person you do not know

Here, に marks the target of the action.

も means also, and sometimes it can feel like even depending on context.

So 知らない人にも suggests:

• also to people you don't know
• or even to strangers

The nuance is that kindness should be shown not only to familiar people, but to strangers as well.

親切 is a na-adjective meaning kind or kindly depending on how it is used.

When a na-adjective modifies a noun:

• 親切な人 = a kind person

When it modifies a verb, it becomes adverbial with に:

• 親切に話しかける = speak kindly

So in this sentence, 親切に describes how someone speaks.

話す simply means to speak or to talk.

話しかける means to speak to someone, especially with the nuance of starting a conversation or initiating contact.

So:

• 話す = talk / speak
• 話しかける = address someone / start talking to someone

In this sentence, 話しかける is a better choice because the idea is actively reaching out to other people.

The こと turns the verb phrase into a noun-like idea.

• 話しかける = to speak to someone
• 話しかけること = speaking to someone / the act of speaking to someone

Japanese often uses verb + こと when talking about an action as a concept.

Here, 話しかけること becomes the thing that is being judged as important:

• 話しかけることが大切 = speaking to people is important

In 話しかけることが大切, the が marks the thing that is important.

So the structure is:

• X が 大切 = X is important

Here, X is 知らない人にも親切に話しかけること.

So the sentence is saying: Kindly speaking to even people you do not know is important.

When Japanese quotes or reports a thought with と, the content before と usually appears in plain form.

Since 大切 is a na-adjective, its plain form is 大切だ.

So:

• 大切です = polite form
• 大切だ = plain form
• 大切だと思います = I think it is important

This is normal Japanese: the quoted thought is in plain form, and the main sentence ends politely with 思います.

This is very common in Japanese.

Japanese often uses:

• plain forms inside modifiers and quoted thoughts
• a polite form at the end of the sentence

So in this sentence:

• 知らない人 uses a plain form because it modifies a noun
• 大切だ is the plain form inside the thought quoted by と
• 思います is polite because it is the main sentence ending

This is not considered inconsistent. It is standard Japanese.

と思います means I think.

Using it makes the statement sound:

• a little softer
• more personal
• less direct or absolute

Compare:

• 大切です = It is important.
• 大切だと思います = I think it is important.

The second version sounds more like the speaker is offering an opinion rather than making a flat statement. That is often preferred in Japanese, especially in polite or sensitive contexts.