Zack Polanski said he remains concerned over the actions of police officers who arrested the suspect in the Golders Green attack, after previously apologising for sharing a critical social media post.
The Green Party leader told the BBC everyone who works in public service "should not be above scrutiny" and action must be "proportionate no matter how brave".
Polanski apologised on Friday for "sharing a tweet in haste" after he reposted a message on X accusing officers of "repeatedly and violently kicking a mentally ill man in the head when he was already incapacitated by Taser".
Communities Secretary Steve Reed said it was "shameful" that Polanski was "still questioning the police's response".
His repost was criticised at the time by Metropolitan Police Commissioner Sir Mark Rowley, who accused Polanski of amplifying "inaccurate and misinformed commentary" in a letter published by the force.
Pressed on whether he believed the police were heavy-handed, Polanski told the BBC's Sunday With Laura Kuenssberg: "I was very concerned by what I saw and I remain concerned."
The London Assembly member said he apologised because social media was "not the appropriate forum to have that concern", adding he believed the commissioner's open letter "also wasn't necessarily the appropriate forum".
Polanski said he has asked to speak with Sir Mark about the issue.
After the show was aired, Labour minister Reed said: "Polanski's apology clearly means nothing given he continues to denigrate the actions of our brave police officers."
The row came after two Jewish men, Shloime Rand and Moshe Shine, were stabbed in Golders Green, London, on Wednesday.
Essa Suleiman, 45, has been charged with three attempted murders.
He is also accused of attacking Ishmail Hussein, a man he had known for around 20 years, in Southwark, in London, on the same day.
The Golders Green victims have been discharged from hospital after sustaining serious injuries in the attack, which was declared a terror incident by police.
In response to the attack, Prime Minister Sir Keir Starmer called for police to prosecute people chanting "globalise the intifada" during demonstrations, labelling it an example of "extreme racism".
Polanski said he did not agree with Sir Keir's view before saying he would "discourage" the use of the phrase but he is "not interested in trying to police people's language".
He added: "I think it's important that we make sure that we have freedom of speech in this country and freedom of protest."
Polanski, who is Jewish, described himself as pro-Palestinian and someone who "cares about Jewish safety", adding: "There's no conflict in those positions."
Transport Secretary Heidi Alexander told the BBC the government is "not talking about an outright ban" on protest but will take "steps that are appropriate to deal with this problem".
Conservative Party leader Kemi Badenoch called for a moratorium on pro-Palestinian marches, saying they are "creating a climate that is normalising a hatred towards Jews and I think they need to be stopped".
The term intifada came into popular use during the Palestinian uprising against Israeli occupation of the West Bank and Gaza Strip in 1987.
Jewish groups have described the term as a call for violence against Jewish people. Pro-Palestinian groups have said it is a call for peaceful resistance to Israel's occupation of the West Bank and actions in Gaza.
In December, the Met and Greater Manchester Police said they would adapt their approach to the slogan in the wake of the attack on a Jewish festival on Australia's Bondi Beach, and arrest those using it in chants or on placards.
