It’s not even really narcissism.
Here’s the original paper describing what is now called Dijkstra’s Algorithm: http://www-m3.ma.tum.de/foswiki/pub/MN0506/WebHome/dijkstra.... Note that the algorithm isn’t called that anywhere in the paper. In fact, it’s not even named.
When other people want to discuss that work, they need to call it something, and some natural solutions are “an algorithm proposed by Dijkstra” and, subsequently, “Dijkstra’s Algorithm”, as you can see in this contemporary paper. https://www.ams.org/journals/qam/1970-27-04/S0033-569X-1970-...)
As that second paper shows, you can’t really call it “the Shortest Path Algorithm” because others were developing other approaches for similar problems. “Shortest Path, Assuming All Edge Weights are Non-Negative and You Can Afford to Search Blindly Without a Heuristic, Algorithm” doesn’t really roll off the tongue either.
a) It'd need to be called that by Dijkstra himself to be even arguably narcissistic and
b) The qualifier "Dijsktra's" is important because there are other algorithms for finding a shortest path (Bellman-Ford, Floyd-Warshall, A*), with different trade-offs (Bellman-Ford is slower, but can handle negative weights; Floyd-Warshall gets you all pairs and may be better when the graph is dense). Accordingly, I think the grandparent's suggestion of purely descriptive names isn't feasible.
"Boolean" and "conditional" are semantically very different, the difference is significant.
The "there can be more than one" is specifically why it's important to call the algorithm Dijkstra. It's possible to look it up in Google or in a textbook and immediately find the algorithm in question. Generic terms don't have that property.
Calling this narcissism does everyone a significant disservice.