Besides the anti-Brexit politicians there are also a number of pro-brexit politicians who didn't support the deal Theresa May is "negotiating" because the terms sucked so hard. That deal is being perceived as being more similar to a surrender than a divorce.
Meaning, this outcome doesn't indicate to pro-brexit politicians changing their minds to remain. Nobody knows how this is going to turn out yet.
Meanwhile, the elections for EU Parliament are coming in May, so it'll be interesting to see how that turns out. That outcome could conceivably affect the Brexit negotiations.