Moreover, there hasn't been a ban on research on the subject of gun violence - it is simply that this is the first time money specifically for research on that topic has been allocated.
Possibly but not probably. Once a situation becomes politically interesting any action or inaction could potentially be the more political act.
If only highly political actors are asking for more research then doing nothing is simply fiscal prudence and not an especially political act. I expect a lot of research on violence has already been conducted and the answers to any questions are probably already known. I don't normally see people in this debate saying 'we don't know X', they say 'we know X' and someone else says 'that is true but misleading/not important enough to justify Y/think of the children', etc.
That's how gun people feel about researching gun violence.
Also as an aside your point about existing data not correlating with homicide rates is particularly non compelling because it doesn’t normalize for firearm kind (handguns are more likely to be used in homicides than other forms of firearm) nor victim type (firearm ownership is massively correlated with domestic murders) statistical collection bias (the Las Vegas mass shooting was not included in national homicide statistics) or the massive scale difference of the US vs the rest of the world (we have a lot more murders of all type).
But here is the thing bad data is _easier_ to manipulate. Every good actor should be cheering expanded research into this issue because it gives all of us a better framework to reason from.