What is illegal?
Porn may not be to everyone's taste but (most of) it isn't illegal in many jurisdictions.
ML algorithms could be trained, to varying degrees of success, to try and spot any type of asset on the Internet. Any government could (and many probably will) use such available technology to apply the laws as best they can in their jurisdiction. If the ML algorithms are good enough then it may help a government apply them more assiduously so it is the laws defining something as illegal which need the scrutiny not so much the fact that better algorithms exist for identifying content.
In the UK there are types of material online that are deemed illegal both reasonably and popularly so. We have the opportunity to vote for politicians to update those laws (or not) as we democratically wish. In other countries, the law on what is acceptable content may be less to your personal taste while there is little or no mechanism for influencing them.
Biting the hand that feeds IT
