I think that in contrast to Soul Calibur, this happens because the attacks are so fast. Watching for every string to stop at every move makes block punishing too hard in Tekken, if everything in the string was around the same level of frame disadvantage on block. Soul Calibur, by contrast, has most moves enough slower that you can identify the string ending in time to block punish when possible. But as a side effect, attacks in Soul Calibur can recover when they look like they recover. (For the most part. There are always weird exceptions.) So as a result, even when you don't know the game, attacks feel far less clunky than Tekken.
Combine that with Tekken's really bad movement (until you learn the mechanics that exploit the way input is handled), massive move lists, and very little input portability between characters, and you get a really frustrating experience that's mostly unique to starting to play Tekken.
It does not apply to top-players, obviously, but for players in the middle of the distribution curve Tekken can be hell.
Or, just preemptively jump earlier and get lucky? The neutral game in Tekken is much more complex and those are all, AFAIK, unsafe strings that will get you blown up. Combine that with the fact that tekken is 3/5 instead of 2/3 by default, and you're never going to win a game against someone that's competent if you don't know what you're doing.
> This is coming from someone who has played every SF since SF 2 and every Tekken since Tekken 2.
I'm a fairly competitive player in the games I focus on: I consistently make it out of EVO pools, and take games off of top players. I haven't played much Street Fighter since SF4, but I can still take games off of good players just playing basic guessies. I've actually put time into Tekken, and the defensive responses are all nonsense, and if you don't know them, you will just eat shit until you die. No button masher is going to be able to respond to Kazuya 50/50ing them with hellsweep and ff3, because the response makes no sense (step to his left??) and is not even a button you can mash.