In particular Deepa (and I) want to know if there's a downside to using the LIKE expression when matching against the tag names (here on line 90)? Was this just overlooked by the core team or is there a good reason to avoid LIKE here?

P.S. It looks like the static $iteration variable may be unused? PHPStorm will tell you that by coloring it gray :)

I believe that using LIKE in search queries for tags will just be too slow, in particular for bigger Elgg databases.  Tags are stored in elgg_metastrings table. This table does not have a FULLTEXT key on the text column (where a tag is stored).  It has an index on this column, but indexes don't help searching for substrings. To my opinion, it is a big performance issue.