Nothing to do with promises, it's about intent, and the actions already taken against these companies by governments around the world that you'd consider left wing(Nice job picking a single point and ignoring the rest again). I think you're confusing liberals with socialists at best, liberals are essentially just excessively politically correct capitalists, still much closer to neoliberals like Bush and Blair than they are to socialists in their policy, this is why calling everyone "left of trump" a socialist even when they're blatantly just left leaning capitalists just causes confusion. Socialism is about economic policy and structure, has nothing at all to do with political correctness or social policy. The hard left has vocally had a problem with these companies for far longer than the right, the fundamental way these companies were exist is incompatible with socialism, just because now a few conservatives got deplatformed because the algorithms used to remove radical Islamic terrorism also happen to catch the same kinds of violent rhetoric in people like Tommy Robinson doesn't suddenly make it a left vs right thing(you realise it's pre-trained neural network algorithms from separate anti-terrorism initiatives that are catching out most of these people, with no human involvement or possible political intent right? The irony is that white supremacists and their supporters use exactly the same language, techniques and rhetoric as extremist Muslims, two sides of the same coin) and throwing the word socialism at anything you think is bad, even things actual socialists have hated for decades, shows you have no actual interest in discussing politics and instead just want to throw loose bogeymen terms at things you don't like while offering no solutions. Big tech directly opposes the fundamental goals of socialism, claiming that socialists want large private companies to have any kind of power at all is a clear and fundamental misunderstanding of the defining policy & common goal of all forms of socialism (for the workers to seize the means of production). Sure, liberals might love big tech, but liberals are still right of centre(free market capitalists) when it comes to economic policy, they're only left wing in a social policy sense.
The differences of capitalism and socialism are whether you want a regulated/planned economy as opposed to an unregulated/free market one, really simple, do you want your economy dictated by the laws of nature, or scientific analysis? Both are valid and non-dangerous options and saying otherwise is rhetoric, some people just think one could offer a fairer, and therefore eventually more prosperous society. (All Marxism is, or any writings by Karl Marx, were empirical-scientific analysis' of the distribution and trade of capital and the system that dictates it, which Marx called Capitalism, Marxist writings are purely just a scientific analysis of capitalism, particularly in 19th century Britain & Europe but much of it hasn't aged at all which is why people still consider it relevant, some men 150 years ago predicted events happening in our economy today and their predicted solutions seem no less relevant to our problems including the original one we were discussing, the type of media & automation has just changed).
So I'll talk policy directly and we can drop the labels, how do you plan to oppose these companies and reduce their power, if not by the method of further regulation? (Currently already being pursued and enforced by groups like the EU where possible within their jurisdiction)
Presumably Trump has some kind of plan at least?
