There seems to be a little confusion here...
Firstly,
only people qualified in W+B can PRODUCE a DCS loadsheet, which should be electronically signed by them. This job is usually done by a loadcontroller where handling agents are involved.
Secondly,
there is the function of traffic officer. This is the person who's legal responsibility is to confirm that the aircraft is loaded as per the loadsheet. This is done by checking that the aircraft data is correct (DOW, DOI, crew config etc.) and also making sure that the LI/R matches the loadsheet. Obviously this can only be done by someone who is actually at the aircraft. The traffic officer is then also required to countersign the loadsheet to confirm that it is an accurate representation of the actual load, after ajusting it by use of the LMC section, if required.
Any dispatcher who does not wish to countersign a loadsheet either does not know if the aircraft is loaded correctly and therefore is risking the safety of all on board or is unable to accept the responibility the position requires and should not be in the job in the first place.
Just to recap.
1. the person producing the loadsheet should sign it (electronically for DCS).
2. the loadsheet must be checked and countersigned by someone who can confirm that it matches the actual loaded state of the aircraft.
3. the captain must sign it to state that he/she accepts it (also known as authorising)
Have a nice day now.