Generally speaking, better voter turnout usually favors the Democrats. There may be demographic reasons for that - e.g. younger people tend to lean progressive but also don't vote as actively as more conservative older people. The impact varies by state, in some states it doesn't really matter much because of gerrymandering etc, but some red states may be seeing significant population growth or increased migration of younger people, who could tilt the balance towards Democrats if they voted.
Automatic registration is perceived as making it easier to vote for people who otherwise wouldn't, i.e. increasing turnout and therefore benefiting Democrats. I'm not sure it really works that way... if someone is too lazy to vote they probably won't do it anyway or won't even know they've been registered.
But "voting fraud" is a good dog whistle for trumplings so they'll make shit up about illegal immigrants and dead people being automatically registered and fight that straw man.
Thanks for the explanation, I had assume it was mostly about the political leaning of some demographics, indeed.
However, if this is a matter of how younger generations think politically, it would safe to say that the Republican party as stands today will fall from grace even more eventually, because they do not seem to be interested onto appealing to the youth anymore.
If your party does better, the hardest it is people to vote, then I would say it is something wrong there... and something hypocritical as well, since we are talking about democracy,etc.
Also, what is gerrymandering? it is the first time I have read that work on internet.