If you're quoting a quote directly from a secondary source (like a 'news' article), and that quote has bracketed content, you should retain the bracketed interpretation and cite the secondary source (as the source of the quoteed material) along with the original source themself (as the source of the unbracketed material).
If you suspect the interpretation isn't accurate, you will need to do some digging to either reach out to the reporter to obtain the recording of the original source, or just reach out to the original source themselves in order to hear the same information first hand (which is probably best any way since you could be able to discuss the interpetation with the source directly).
If you don't have the time or will power to do all of that digging, then you're relegated to retaining the bracketed interpretated language and citing both the secondary and original sources since the quoted language is now a hybrid of ideas from both sources, delineated by brackets.
If you're quoting a quote directly from a secondary source (like a 'news' article), and that quote has bracketed content, you should retain the bracketed interpretation and cite the secondary source (as the source of the quoteed material) along with the original source themself (as the source of the unbracketed material).
If you suspect the interpretation isn't accurate, you will need to do some digging to either reach out to the reporter to obtain the recording of the original source, or just reach out to the original source themselves in order to hear the same information first hand (which is probably best any way since you could be able to discuss the interpetation with the source directly).
If you don't have the time or will power to do all of that digging, then you're relegated to retaining the bracketed interpretated language and citing both the secondary and original sources since the quoted language is now a hybrid of ideas from both sources, delineated by brackets.