They mean any party that's had majority control of parliament, they don't mean it's been used as a strategy to get there but rather once they're ruling it's been introduced
It's not what the comment meant, but worth adding that the UK security forces have wanted this ever since they lost the ability to read everyone's mail and listen to our calls. They actively lobby every sitting government for this kind of bill, and (I have no doubt) promise all kinds of support for politicians who push their agenda.
It's similar in concept to 'in power'. The government holds office, rather than it being in power. It's more to say that the power isn't derived from the government itself, but the office they are elected into.
Every government to hold office = every previous party that was elected and formed a government