A 'Time To Go, Massimo' poster appeared on an advertising board outside the East Stand on Thursday.
The poster was paid for by supporters angry that Cellino has not sold his 75% share in the Championship club.
"He has been very positive even through the dark days and bad performances," Raynor told BBC Radio Leeds.
"People will do what they want - they'll protest or they won't protest. If we win some football matches there will be less people protesting."
Cellino agreed in principle to sell his majority share to supporters' group Leeds Fans United in at the end of last October, but changed his mind a week later.
Fans have also been left angry about a 'pie tax,' which saw the club raise the price of Championship tickets in the South Stand by £5.
Cellino is currently appealing a ban from the Football League that would prevent him running the club.
"(Cellino) has talked about the future. He has been supportive in bringing in the three players we've already brought in," Raynor added.
"The biggest frustration for us is that we haven't been winning as many games as we should and that doesn't help matters."
Leeds, who are currently 16th in the Championship, have won just one of their last eight league games.

Frenchman Christophe Borgye's remains were found at a property in Ellesmere Port, Merseyside, in 2013 - four years after he was reported missing.
Manuel Wagner, 29, has been found guilty of murder and sentenced to a minimum jail term of 16 years following a trial at Liverpool Crown Court.
Two other men were convicted in 2014.
Mr Borgye, 36, was killed in May 2009 and buried in the outbuilding of the house he shared with German national Wagner and fellow Frenchmen Sebastian Bendou and Dominik Kocher.
Bendou contacted Cheshire Police in May 2013 and led officers to Mr Borgye's body, which was wrapped in tarpaulin and encased in thick concrete.
Officers said a low brick wall had been built inside the outhouse with three layers of concrete placed over the body.
A post-mortem examination found My Borgye died from hammer blows to the head.
He had been reported missing by a work colleague, but after launching an investigation police said they believed he had left the country.
Det Sgt Steve Currie said the case had been "complicated" and "devastating" for Mr Borgye's family, but added "the final jigsaw piece in this shocking crime is now in place".
Wagner was previously found not guilty of assisting an offender and preventing a lawful burial.
However, was re-arrested in 2015 when new evidence came to light.
Bendou, now 39, and Kocher, now 38, were given life sentences for murder with minimum terms of 14 and 23 years respectively in 2014.
Leeds United's assistant head coach Paul Raynor has said that chairman Massimo Cellino is still positive, despite fan protests at Elland Road.
[NEXT_CONCEPT]
A third man has been jailed for murdering a flight attendant who was bludgeoned with a hammer and buried in a concrete tomb.