Bangladesh police are investigating the murder of an Italian aid worker who was shot on Monday, with the Islamic State group saying it is responsible.
The two-Test series was due to begin in Chittagong on Friday, 9 October.
"One man gets killed, an Italian, and the tour is off. We've had 50,000 people killed in Pakistan," Khan said.
Khan was referring to figures estimating the number of "fatalities in terrorist violence" in Pakistan since 2003.
In May, Pakistan hosted their first home full international fixture since gunmen attacked a bus carrying the Sri Lanka team on its way to play in Lahore in 2009.
"A certain amount of tension is likely through terrorism, but they have to trust the Bangladeshis, the Indians, the Sri Lankans and Pakistanis. We give them 100% protection," Khan added.
"Some of the countries, like Australia and New Zealand, are perhaps oversensitive."
Cricket Australia had initially delayed the team's scheduled departure on 28 September while it worked on a "revised security plan".
But it now says that official advice means it had "no alternative but to postpone the tour".
The Bangladesh Cricket Board (BCB) said it was "disappointed" by the decision but is "committed to rescheduling the series at a later date".
On Wednesday, the BCB had promised "VVIP" treatment for the Australian team, saying they would be given the same level of security afforded to visiting heads of state.
England are due to tour Bangladesh to play two Tests and three one-day internationals in October and November 2016.

The 25-year-old Spaniard agreed an initial three-year deal with the Whites last summer after moving to Craven Cottage from Rayo Vallecano.
However, he has not made a first-team appearance for the Championship club since October.
Celta are ninth in La Liga and will face Ukrainian side Shakhtar Donetsk in the last 32 of the Europa League.
Find all the latest football transfers on our dedicated page or visit our Premier League tracker here.

Chay Roberts-Jones was working at Blundells School at Tiverton, Devon, when he assaulted the girl under the guise of giving her a sports massage.
Roberts-Jones, 29, was cleared of sexually assaulting two other girls at a summer ball and a camping trip by a jury in February at Exeter Crown Court.
He was a physics teacher at the Â£31,000 a year school but now lives in France.
The court heard details of the conviction are to be supplied to the French authorities to ensure Roberts-Jones, previously of Preston Street, Exeter, is not able to work with children again.
In May 2014, he offered to give his victim a massage after she suffered cramp but went on to lift her top and try to pull down her trousers.
Recorder Mr Philip Mott, QC said there was a "higher culpability because of the abuse of trust".
He said: "This was not just flirting and an error of judgment but a more determined effort to pursue your desire and overcome her resistance."
The judge said Roberts-Jones, who now teaches adults in France, had experienced "substantial punishment in terms of career, self image and place in society" and suspended his sentence for two years.
He ordered Roberts-Jones to pay Â£2,500 costs and sign on the sex offenders register.
Emily Cook, for the defence, said there was an "element of infatuation" with the victim which "got out of hand".
Australia were "overly sensitive" to postpone their tour of Bangladesh over security concerns, says Pakistan Cricket Board president Shahryar Khan.
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Fulham midfielder Jozabed has joined Spanish La Liga side Celta Vigo on loan until the end of the season.
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A public school teacher who groped an 18-year-old girl has been given a nine-month suspended sentence.