Why professional records are not private data
Player data draws a reasonable question about privacy, and it deserves a direct answer rather than a disclaimer.
What this source publishes about a player is a professional record: which clubs they were registered with, in which seasons, how many appearances they made and how many goals they scored. That is the same category of information as a footballer's entry in a match programme, and it is published because it is the public record of a professional activity. It is not contact details, not health information, not anything about private life, and we collect none of those.
Where care is genuinely needed is youth and amateur competitions, because the same database structure that holds a professional's career can hold a sixteen year old's. We scope competitions explicitly rather than crawling everything available, and a brief that would sweep up minors gets flagged at scoping rather than delivered quietly.
The second reason to use this source is the long tail. A dataset limited to major leagues answers major league questions; the value of a broad source is in the divisions and federations nobody else structures consistently.
The third is that career records connect across clubs and countries, which makes player movement analysable without a transfer database - the appearances themselves show where somebody went.