Thought-provoking article on #rdf vs #lpg models: https://neo4j.com/blog/rdf-triple-store-vs-labeled-property-graph-difference
The "user likes user" example was a poor choice for counts (it makes no sense, and RDF has the correct idempotent behavior). Representing a grocery order would be more compelling: "user purchased foo" is awkward in RDF for counts. However, "user fooPurchaseCount n" is tenable together with "fooPurchaseCount purchaseCountFor foo". More steps? Yes. Impossibly inconvenient? No.
The "different flights with same departure and destination locations" example also isn't convincing: the flights are distinct, so we have "flight1 a flight", "flight2 a flight", "flight1 source cityA", "flight1 dest cityB", "flight1 cost 123", "flight1 dist 4100", etc for flight2.
I don't see any modelling problem here, either. In fact, the granularity of RDF gives incredible querying flexibility.