against

both are correct...the first one is only talking about the "garments" not the import. the second is talking about the "importing" itself

i assumed you deliberately ignored the punctuation

But some references said that- the second one is wrong. Because no object has been added after the word 'importing'. If I write-"They showed arguments against importing garments", then it will be correct.

And for first one some references said that it is also wrong. If I write-"They argued against imports"/"They argued against importing garments", then it will be right.

But you have said both of these are correct. Now I am confused. Please, help me.

It all depends on what you want to say:

1. They argued against imported garments.

1. They argued against importing garments.

1. They argued against garment imports.

Neither sentence is correct, Punkey's examples are.

The first sentence is plain wrong, either imported or importing. Imported implies a particular foreign suppliers goods are problematic, either poor quality, too expensive, poor supply. Importing suggests being against all imported garments.

The second sentence is alright (ish) but it's vague, it could be any import. People don't tend to show arguments for or against, they tend to show both for and against so their audience can make a decision.