Actually - I took a closer look. The explanation is perhaps simpler.

Tide doesn't make a stand-alone fabric softener. Or if they do - amazon doesn't seem to have it? There's TIde, and Tide with Fabric Softener, and Tide with a dozen other variants - but nothing that's not detergent plus.

So - no point in differentiating. The little Ad-man in my said says "We don't sell mere laundry detergent - we sell Tide!"

To put it another way - did you ever go buy to buy detergent, and accidentally buy fabric softener? Yeah, me neither. So - the concern is perhaps unfounded.