Annual cleaning leaves a lot of time for bacteria to grow.
Here are a few studies by researchers at Penn State. I’d trust them over recommendations by the turf manufactures.
https://plantscience.psu.edu/research/centers/ssrc/documents/staph-survival-on-synthetic-turf.pdf
https://plantscience.psu.edu/research/centers/ssrc/documents/staph-survey
Edit: lots of variables that go into it, like the amount of UV light (good), how recently played on (bad), to the temp (cool/dry good) - but do places run the AC non-stop between events, to how well uniforms are washed (another article on Colgate U and what they’ve ended up doing), and whether skin is exposed and/or open cuts/abrasions.
That last variable is troubling for soccer. The NFL has recently had MRSA issues that forced a few players to retire, and yet they have uniforms that cover way more exposed skin, whereas with soccer and slide tackles, there’s a chunk of leg fully primed for burns and subsequent exposure. Makes sense why some players pull their socks above their knees to where the shorts/compression shorts extent to.