It's true that if it falls within household exemption then GDPR doesn't apply. However household is exemption is narrow.
For example CCTVs that point to public street are not within household exemption scope even if you are only doing it personal protection.
In the context of this app the video was taken and posted to YouTube for everyone to see. So it would no longer be within household exemption -> the original author would have needed to fulfill their GDPR obligations.
And in regards to Article 11, that does not give exemption for Article 13/14, only for 15-20.
Platforms tend to rely on Article 14(5)(b), but I don't think that it would often hold up if challenged. CJEU puts a lot weight on Article 13/14 since they the primary ways for data subject to even find out about the processing. And if they don't find out the processing they cannot effectively exercise their other rights.
For example CCTVs that point to public street are not within household exemption scope even if you are only doing it personal protection.
In the context of this app the video was taken and posted to YouTube for everyone to see. So it would no longer be within household exemption -> the original author would have needed to fulfill their GDPR obligations.
And in regards to Article 11, that does not give exemption for Article 13/14, only for 15-20.
Platforms tend to rely on Article 14(5)(b), but I don't think that it would often hold up if challenged. CJEU puts a lot weight on Article 13/14 since they the primary ways for data subject to even find out about the processing. And if they don't find out the processing they cannot effectively exercise their other rights.