I get the impression that it isn’t a redundant use; but a use with a different meaning(of which you have no obligation to approve; but it is definitely in common use).
If you mean ‘modern’ in the historian sense; then most of those uses are either redundant or just plain wrong(depending on where you stand on the start and/or existence of ‘postmodern’, things like web browsers may not have existed during the modern era); but much of the use of ‘modern’ seems to be intended to mean ‘contemporary; and recognizably distinct from prior examples that are deemed to be of the same category’.
One can debate the wisdom of choosing this word for this purpose; but it is arguably a thing that deserves a word. ‘Contemporary’ doesn’t cover it; since something can be contemporary regardless of whether it is wholly novel or just the latest iteration of a group with historical examples; but one cannot be ‘modern’ in this sense without being contemporary and having antecedents that are recognized as being of the same kind but sufficiently distinct in detail. If something’s antecedents are too disimilar to be treated as ‘the same thing’ it doesn’t usually get called 'Modern Thing"; but just “Thing”; and if the antecedents are too similar to be lumped together as recognizably old it might get to be ‘new thing’ or ‘contemporary thing’; but not ‘modern thing’.
(edit: in thinking about it, things can be ‘modern’ in this sense without necessarily being contemporary; so long as they share enough details with the contemporary member of the group and differ enough from the ‘old’ members of the group that they cannot be described as ‘old’. An iphone 5, say, is now two generations past being contemporary; but it falls on the side of ‘modern’ rather than ‘old’ because it’s essentially just slightly slower than the iphone 7; while it differs wildly from one of the later WinCE or PalmOS cellular phones.
The essence of this use of ‘modern’ seems to be in having predecessors that are deemed to be of the same ‘kind’(exactly how this determination is made appears to be sloppy and unsystematic; and can vary depending on the audience and the context; but however ugly the method, the determination is made); but to differ in enough generally recognizable ways that a satisfactory line can be drawn between ‘the modern’ and ‘the old’: ‘The modern’ does have to include whatever iteration is contemporary, Middle Egyptian is not ‘modern’ just because it is newer than Old Egyptian, similar in kind; but recognizably distinct, since it isn’t even remotely contemporary; but now-dated items are allowed to be ‘modern’ so long as they fall on the same side of the distinction as the contemporary item.
This also explains why people use terms like “architecturally modern”: to describe something that isn’t true modernity; but is similar enough in some respects to what is modern to be worth qualified mention.
