I think it has to do with overloading the ribbon conductors, if you have one continous run, the load at 12 volts would be 5 amps, with 24 volts it would be 2 1/2 amps. I have seen many low voltage lighting installations burn up because nobody did the load calculations. They think just because it's low voltage and low wattage it doesn't matter how many lamps they put in there. The wire in the ribbon cable is probably only rated at 5 amps.
Agree, the conductors in the LED tape will be relatively small and probably cant safely handle more than 5 amps.
I have installed loads of LED lighting tape here in the UK, this comes in 6M lengths, with a loading of just under 30 watts at 12 volts DC, or nearly 2.5 amps.
The suppliers warn against connecting more than one 6M length together.
Each length should be connected to its own 30 watt driver unit, or alternatively up to 8 lengths may be connected to a 250 watt driver, but in this case each length must have it own wire and 3 amp fuse, NOT be connected end to end.
Sounds as though the product to which the O/P refers is similar, but rated at 5 amp not 2.5