Because, I know from past experience, that only a small minority of these 'incels' have done anything seriously wrong, and the rest are going to end up on government watchlists for expressing the wrong political opinions. Political opinions that have been deemed inappropriate by pressure groups which are influencing the government to enforce their agendas.
And because of the lack of separation of powers nowadays, we will have intelligence agencies such as GCHQ monitoring the Internet, using powers that should be only used against foreign states, turned against the general public to hunt down these 'incels'.
Yes, these pressure groups have so much sway over the government, they can even eventually get GCHQ to enforce their agendas. Many of these pressure groups being fronts for those with radical feminist or evangelical christian agendas, i.e. they are the modern equivalent of puritans.
This stuff plays out over the decades, and finally we got to the point where we are now, after extensive lobbying by these groups for a very long time indeed.
And it's ruining society, these pressure groups are in effect, a national security issue and nothing is being done about it by the government.