Ok, let's talk SMS in the context of the list I wrote.
What has SMS? Mostly it is riptides, skyrays, and devilfish.
The SMS on riptides are pretty much guaranteed to blow up a single venomthrope thanks to ripple fire, and the BS4 on the skyrays means they should down one, the devilfish at BS3 is a crap shoot (1.33 wounds to one). However, outside of the devilfish, having such nasty weapon systems using only a part of their firepower to drop a venomthrope is just a win IMO.
The vehicles in that list are probably not going to be too close up to the line, and the riptide MIGHT be, but it is probably hanging back a bit.
If the Tau player is going first, it should be possible to put the venomthropes out of LOS, out of range of SMS, and still in a position to hand out shrouding.
Now, if the Nid player goes first, they can just move up en masse and, mostly likely, just take their lumps, but the turn 2 charge potential is strong and there should be lots of threats out there.
Now, the skyrays and the devilfish are nice targets for lictors charging solo as with all their S6 attacks they can easily shut those down.
The Riptide is threatened by getting pinned by the broodlords and if it could also be bothered by the rending attacks of the stealers and lictors (though that's not ideal either).
Look at all the threats that are there for the Tau on turn 1 and 2.
Do you kill all the lictors/genestealers in front of you that could kill lots of your stuff? Do you go after the Swarmlord? Do you go after the Venomthropes? Do you start whittling down the giant horde of gribblies? Do you take down the Carnifexes?
Tau shoot lots, they are tough, but the issue that this army presents is that there are so many things to shoot at. IMO, by the time the venomthropes would be in danger of being SMS fodder, they have already done their job.
Honestly, the real issue that Tau present for this list is the shooting of things like missilesides and just lots of kroot or firewarriors with ethereal support.