While it's fair to say that we have a lot of things we wouldn't such as Holiday Pay and Occupational Sick Pay because of the campaigns of the unions in the past, they can go too far at times.
I've been a member of a union since I started work to benefit from collective barging etc but have never once voted for strike action as it's ultimately pointless and may just vindicate the decision made by an employer anyway.
Jobs at risk? Yeah let's show 'em whose boss by not turning up for work.
Better to let the union trained negotiators do what they are employed to and negotiate on your behalf.
I don't think lack of recognition of a particular union is grounds for a strike but I do back strikes if the health of workers is at stake.