No, TarSpiel's claim is not a guess because the data sources used to assess this question are not what you think they are. Try this for starters (it's the first google result, FYI)
"Going beyond existing research, we utilize data from the Texas Department of Public Safety, which checks and records the immigration status of all arrestees throughout the state. Contrary to public perception, we observe considerably lower felony arrest rates among undocumented immigrants compared to legal immigrants and native-born US citizens and find no evidence that undocumented criminality has increased in recent years."
And when you say, "illegal immigration is too high and it makes us unsafe," and then say, "whether or not my claim was true, we have too many" that is in fact denying reality matters. It's like when people say, "Roy would be a better coach if he would just call timeout," and then they are presented with solid evidence that calling TO in the middle of a run actually has no effect on game outcomes, and they respond, "well, he should still call more timeouts." They are saying that reality doesn't matter to them. They have decided, without any evidence, that Roy should call more timeouts.
The most insidious thing is the repetition. See, if you would admit that you were wrong about this or about calling timeouts, then maybe the next time you feel the need to make that complaint, you'd remember that it was in fact false. But that's not what you do. You just drop the subject, cling to your errant beliefs, and then we have to rinse and repeat later. Over and over again, the same zombie BS keeps rising.
To be clear: YOU ARE WRONG ABOUT CRIME AND ILLEGAL IMMIGRANTS. It is not a matter on which reasonable minds disagree. We went through this on the old board too, and back then you were challenging math. Have you accepted that yet, or are you still struggling with 5th grade math?