That is correct. Enemy air defense are very powerful.
In one of my missions, I had ships firing Tomahawks at targets, and it was the Player's job to take out the SA-10 sites which would shoot down the Tomahawks.
There is another problem with the Tomahawks, in that they don't seem to do the kind of terrain following that the SLAM's will. If you have a target behind a hill, or other obstacle, the Tomahawks seem to slam into them rather than skim.