How does 해서 work in 우리와 다른 사람을 차별해서는 안 된다?

Question

In the following sentence:

우리와 다른 사람을 차별해서는 안 된다.

(Source: 대학 강의 수강을 위한 한국어 읽기 중급 2)

I don't understand how ~아/어서 construction works in this context. If the meaning is "It is not correct to distinguish people different from us.", then I think the following sentence would be fine.

우리와 다른 사람을 차별하는 것은 안 된다.

But I don't understand why ~아/어서 is used here. Does it mean "Because it distinguishes people different from us, it is not correct."? (But in that case, I think "는 " is not used.)

Or something others?

Answer 1

는 is an emphasizer which cannot be omitted from the idiomatic phrase -아서는/어서는/여서는 안 되다 (Note: The standard dictionary does not have it in an idiom list, but I believe that it is an idiom). Some idioms (including -아서는/어서는/여서는 안 되다) are fixed, and they are not fully relevant to their components. Anyway, 되다 is the "core" word in this phrase; it governs the meaning of the whole phrase. This is why your approach is not working for that sentence.

Although -는 것은 안 되다 is also grammatically correct, most Koreans use -아서는/어서는/여서는 안 되다 for that specific meaning of 되다 ("not to be allowed"). The point is that you should consider collocation.

The phrase -아서는/어서는/여서는 안 되다 is quite equivalent to another idiomatic phrase: -아서/어서/여서 되겠-? Please note that the latter is used to form a rhetorical question and also that the emphasizer 는 is hardly attached to -아서/어서/여서 in the latter. The question

우리와 다른 사람을 차별해서 되겠니?

does not expect an answer, although you can still answer it (for example, "(물론) (차별해서는) 안 되지"). As "우리와 다른 사람을 차별해서는 안 된다" does, this question says what you should / must not do.

Answer 2

There is an expression '-아/어/여서는 안 되다', which means 'should not'.

It is similar with '-(으)면 안 되다' that has more strong meaning like 'must not'.

The verbs with 하다 or the verb 하다 come with '여서는 안 되다' ex) 차별하다 + 여서는 안 된다 = 차별하여서는 안 된다 = You should not

'하여서는' in '차별하여서는' contracts into '해서는' -> 차별해서는 안 된다

or 차별하면 안 된다 = You must not

Answer 3

I found out that the grammatical construction in this sentence is not ~아/어서 + 는 as a subject particle. There is another grammatical construction ~아/어서는, which means something like "doing ~ would" or "if it is ~".

So the sentence means (emphasize such that the ~아/어서는 stands out more):

If there is discrimination against people different from us, that is not correct.

This construction is often used along with ~안 되다 like the sentence on the post. More on this post on HowToStudyKorean.