There are no dumb questions, just dumb answers ... and this might well be one of them
If there is a way to do what you want, I could never find it and had to resort to cut and paste.
That's a pain, but I could see it from DW's point of view. Imagine each pub having many pages, each with say six text objects per page. To produce an effective export might well require that the contents of each object would need to identified and kept isolated from the others.
My suggestion won't help you with your current need, but it might save some heartache with future pubs.
I tend to work almost exclusively with large text pubs, which sometimes have around 100,000 text objects in a pub. When I found that I couldn't export the text without having to resort to cut and paste, I reversed my working strategy.
With any major pub, I now create all my text in a word processor. This gives me a reference file(s) which has been useful when disaster strikes. It also allows me to do more controlled spell checking, grammar checking, case replacements, etc. than is available within Opus.
With Opus 281, I cut and pasted the contents from the WP files to Opus. With Opus 4.5 I save the WP files in RTF format and use the import text tool.
I'm sure others have found better ways to achieve similar results.
HTH