Minimum current for charging a battery
Charging will certainly not stop if you charge with a smaller current, it will just be slower.

The reason to specify the minimum charge current is not entirely clear and not specified in the document you linked to. I can think of at least two possibilities:


This is the minimum current the battery is supposed to draw from a constant voltage charger, that is, a constant 13.8...14V source.
This is the recommended minimum charge current which prevents acid stratification after a deep discharge.


Unless you can find which one it is, I suggest to avoid the situation where your charge current is always below the minimum value, especially if the battery will rarely reach full charge.