The Speakers' Corner should be reserved for protests and demonstrations, said Mr Gilbert Goh, a volunteer at non-profit society transitioning.org.
On Sept 27, NParks allowed YMCA's concert and a protest by #ReturnOurCPF group to go ahead at Hong Lim Park.
Mr Goh, who has organised several large rallies there, said: "We have no alternative site like public non-government organisations have."
Speakers' Corner, set up in Hong Lim Park in 2000, is Singapore's only outdoor venue where the locals are allowed to give public speeches without a Public Entertainment Licence. In 2004, it was expanded to allow performances and exhibitions if the organiser and participants are Singaporeans.
Not everyone agrees with Mr Goh.
Civil rights group Maruah president Braema Mathi said the Speakers' Corner is a space that is "used and valued" by civil society groups, but other groups should be welcome to use it as well.
But organisers should be mindful of holding events at Hong Lim Park especially when they have vulnerable participants. She said NParks can facilitate in negotiations on sharing the space.
Singapore Management University Law Professor Eugene Tan said: "The Speakers' Corner was created as a space for people to express and share their views on a variety of issues, not just politics alone. We would be poorer for it, if we restrict the type or number of use for the space.
"It would be worse if Hong Lim Park becomes like some online spaces - echo chambers in which purposeful engagement is avoided, closed minds preferred and polarised views generated."
So should rules be tightened to prevent a similar incident from recurring?
Management of Speaker's Corner was transferred from the police to NParks in 2008. An online registration system replaced permit applications at the Kreta Ayer Neighbourhood Police Post.
Should permits be handled by the police again?
Worker's Party (WP) member and Non-Constituency Member of Parliament Yee Jenn Jong said he did not favour more rules for Speakers' Corner.
On his Facebook page, he called the actions of the protesters "inappropriate" and added: "Some want to use the space for protests and some want to use it to celebrate. We need not be so prescriptive about what the space can be used for."