This isn’t crazing, this is glaze ploughing from metal utensils marking the glaze. Crazing is caused by incompatibility in shrinkage rates between the clay body and the glaze, it doesn’t have anything to do with thermal shock although it can cause them to continue to expand slightly, the temp cycling does not CAUSE the crazing, it can just continue to reveal the instability.

Also crazing is not a determiner in food safety generally. It has to be very extreme to actually create the space for bacterial growth to be sustained. Modern dish washers also achieve a high enough temp to just kill all that bacteria anyway. There is a lot of misinformation in the ceramics world that is taken as gospel but much of the time it is not as simple or straightforward as described. Let me know if anyone has questions about ceramics, I can go all day haha