In the late 60s, I believe, Consumer Reports tested top loading, one speed washers for how well they handled delicate fabrics. They used an open-weave casement drapery fabric as the victim. The Maytag, and I don't remember if it was a Fabric Matic,  pulled the threads six ways from Sunday and distorted the weave. The Frigidaire was the most gentle.

I guess by then people were too lazy to use the old instructions for using the soak method for washing blankets, sweaters etc. where you filled the tub and dissolved the detergent before adding the blanket, let it agitate for one minute then soak for ten minutes spinning out the wash water and repeating the process for rinse. Frigidaire had the process licked with the automatic soak cycle on some of their washers.

Maytag agitators were always large and the tubs narrow so stuff could get trapped between the fins and the tub. By the late 60s, this probably would have been the power fin and it might have been the open end of the fins catching the woven fabric. Depending on the size of the pieces of fabrics, and how heavily the machine was loaded, the poor turnover that plagued Maytags might have been compounded by the casement fabrics' lack of  resistance to the water currents. This would have potentially allowed the fabric pieces to be mauled longer by the agitator at the bottom of the narrow tub in the space between the agitator fins and the tub wall.

I think the wider tubs of most other makes gave more room between the agitator and the tub wall so that might have been why they were gentler when washing delicate fabrics at normal agitation speed. Common sense would dictate that if you were washing delicates at normal speed, the tub should be full of water and the load should be kept small to allow the water, instead of the fabrics to absorb the force of the agitator.