I can’t speak for why speeding isn’t viewed as badly, but texting is just so recent compared to drinking. Growing up (at least for me, now 26) we were drilled nonstop about how bad drunk driving is. I’m sure that has been the case for a long time. I would assume texting is being taught the same way now, but very few people have grown up being drilled to think that way. It took drunk driving a long time to get to viewed as badly as it is now and I don’t doubt texting will eventually be viewed the same.

Punishment/enforcement for doing them is probably a big one. Getting a DUI can ruin you. Texting used to be virtually nothing (and it isn’t all that hard to get away with either). You can almost always go at least 5mph too fast and no one even cares. Drinking gets harsher punishment, more enforcement, and little leniency compared to others. Those will just make people believe that means it’s worse. And people believing they are worse will keep them more enforced and punishing. A weird cycle that has to be broken. And I appreciate that you are pushing against it. But many people are going to view you as dismissive of how bad drunk driving is rather than listen to what you are trying to say about texting. I think the better way to get perceptions to change is to just focus on how bad texting and driving is, and not focus on comparisons. There are a whole bunch of factors involved in both and trying to compare the two in subjective terms will unfortunately just cause an unproductive argument.