In fact what we really do need is more scientists expressing their political opinions and backing them up with hard facts and of course working to dismantle the lies put out by professional politicians.
A very nice thought, but logic never survives a descent into "my side vs. your side." As soon as scientists enter into the political sphere their points are no longer judged as factual conclusions but as their adopted positions, as one may rightly question whether it was their political conclusion or their scientific conclusion which they arrived at first.
If we don't want science to devolve into "our scientists say this!" and "oh, yeah, our scientists say this!" we need to keep scientists as far away from politics as possible. And, doing so makes it that much easier for politicans to go against their base, "Sorry, guys, I feel you, but the experts say it's like this, so I guess that's what we're going with."
(Try re-imagining that scenario as, "Sorry, guys, but the Democrat/Republican scientist says it's like this" to a Republican/Democrat audience.)