Big Tech is cracking down on Donald Trump, which gives him all the more reason to retreat from its platforms into his own digital ecosystem.

The president’s reelection campaign and some of his followers had already been joining and promoting alternative social media sites, much as the president pressures Fox News when it displeases him by calling attention to its upstart conservative rival, One America News Network.

That was before the most recent wave of crackdowns on Trump and his supporters by social-media firms seeking to remove content that is deemed offensive, inaccurate or both.

On Monday, the social media platform Reddit shuttered “The Donald,” a forum for Trump supporters, as part of a larger clampdown against groups that had violated rules against harassment and hate speech. Separately, Twitch, a video streaming platform owned by Amazon, suspended the Trump campaign’s channel for rules violations.