A lot of people have similar statements, but the use of the word "most" in this context just doesn't matter past some cutoff. The flu is very far on the safe side of that cutoff, and the coronavirus is very far on the bad side.
The flu and the common cold virus behave comparably to the current pandemic. The flu in particular kills about 300K per year after infecting about 20% of the global population. That's a mortality rate of 0.02% and a survival rate of 99.98% for the general population, which is not a fun statistic, but nothing to panic about either.
Critically, the hospitalisation rates for the flu are so low that the current infrastructure can handle it. People still die, but only if they couldn't be saved with medical intervention. Much of the time they will receive treatment and live.
Even if you shift the numbers around a lot -- say, 50% infection rate -- the orders of magnitude come out to about the same. Governments can just put out ad campaigns to encourage people to get the flu vaccine to compensate for a particularly bad flu season.
The critical thing with the cold and the flu is that they move well past the initial exponential growth phase into a "logistic curve" long before the hospital systems become overloaded with the sick. That is, each new strain of the flu runs out of victims by hitting the population ceiling of 7.6 billion. Not everyone is vulnerable, and the rest either become immune or protected by herd immunity.
Now compare this to the Coronavirus. It has a mortality rate of about 0.8% of confirmed cases, with medical care. Much more importantly, about 10% of the confirmed cases required intensive care.
Nobody really knows the ratio of confirmed-to-real cases, but I'll be generous and assume that only 20% of all cases get a confirmed diagnosis, with 80% of cases just shrugging it off as a case of the "sniffles". Similarly, I'll assume that the virus will halt at around 20% of the total population.
For Italy, with a population of 60M people, that's 12 million infected, equivalent to 2.4 million confirmed cases, 240K in intensive care, and 19K dead.
But I lied.
I lied when I said "240K in intensive care". There just aren't that many beds, or intubation kits, or CPAP machines, or even oxygen masks. There aren't anywhere near enough doctors, or nurses, or any resource you care to name. I know this to be true because all of these things have run out already.
Long before the exponential curve starts to "slow down" and become logistic, the entire medical infrastructure becomes overwhelmed and the cases that "would survive with intensive care" turn into "deaths".
Worse, this happened at a "confirmed case count" of about 10K. I said 2.4M above!
The conclusion is that the Coronavirus can overwhelm medical systems waaaaaaay before it hits the "knee of the logistic curve", making it a nearly pure exponential curve. Exacerbating this is the incubation time, meaning that any measure taken today will have essentially no effect for at least a week.
Act now and save lives, act tomorrow and see your loved ones die.
This is the difference.
3blue1brown explains it quite well, and I recommend everyone watch his video: https://www.youtube.com/watch?v=Kas0tIxDvrg