Can't open text file from Finder without extension even though execute flag is not set

Running Big Sur 11.3.1 I've got loads of text (UTF8) data files coming in from another Mac that I'd like to just double click or drag and drop to BBEdit or TextEdit. The files have no file extension and I'm not supposed to be changing the names unless I work from duplicates. The files can be opened from a file dialog but that's a bit tedious. When I drop on BBEdit I get messages that say the file cannot be opened because the developer is unknown and "macos cannot verify that this app is free from malware". That's an absurd message for a text file. Any thoughts on fixing this? (already tried chmod -x)